Nanoantioxidants and Their Potential Use in the Management of Oxidative Stress-Associated Male Infertility

Abstract

The prevalence of male infertility attributed to oxidative stress (OS) is a growing concern globally. Traditional methods to treat male infertility have some limitations, including low efficacy and invasiveness. Additionally, assisted reproductive procedures, such as in vitro fertilization and intracytoplasmic sperm injection, are expensive and carry higher risks. These challenges underscore the need for innovative solutions. A multidisciplinary approach is imperative, drawing insights from fields such as reproductive biology, nanotechnology, and clinical research to effectively combat male infertility caused by OS. Recent advancements in nanobiotechnology provide a promising opportunity to tackle male infertility caused by OS. These advancements enable the design and development of nanoantioxidants (nanoAOXs) and drug delivery systems tailored to the male reproductive environment. This review highlights the recent progress in the rational design of nanomaterials, with a specific focus on nanoAOXs for managing male infertility associated with OS.

Graphical abstract

Keywords

antioxidants / nanoantioxidants / oxidative stress / infertility / male

1. Introduction

Clinicians define infertility as occurring when a couple cannot conceive after one year of regular, unprotected intercourse [1], which could be attributed to the male, female, or both partners [2, 3]. The World Health Organization (WHO) in its latest report states that around 1 in 6 individuals of reproductive age globally experience infertility [4]. On average, the global prevalence of couple infertility is approximately 9%, with variations observed between developed (3.5% to 16.7%) and less developed countries (6.9% to 9.3%) [5]. In the United States, up to 12% of men encounter fertility issues [6]. Notably, male factors contribute significantly to infertility in 20–30% of cases and up to 50% of couple infertility [7].

Male infertility is a complex condition influenced by a range of factors, including genetic, environmental, lifestyle, and medical factors [8, 9, 10]. Various pathologic causes of male infertility include testicular, pretesticular, and extratesticular hormonal factors [11, 12, 13]. Idiopathic male infertility (characterized by no known identifiable causes) accounts for 30–40% of cases [14].

Oxidative stress (OS) due to elevated production of reactive oxygen species (ROS) is a common risk factor for idiopathic male infertility [15, 16]. Sperm rich in polyunsaturated fatty acids (PUFAs) are particularly susceptible to ROS-induced damage, resulting in reduced motility, count, and increased DNA fragmentation [17]. Antioxidants that neutralize these oxidants play a critical role in maintaining the redox homeostasis of a cell [18]. Antioxidants can be taken as single supplements or in combination, including vitamin A, vitamin C (Vit C), vitamin E (Vit E), carnitine, N-acetyl cysteine, coenzyme Q10 (CoQ10), and lycopene, along with important cofactors such as zinc (Zn), selenium (Se), and folic acid [18]. The application of nanotechnology in the pharmacotherapy of male infertility has shown some benefits, such as improved oral bioavailability, increased stability through the extension of drug half-life, targeted drug delivery, and reduced adverse effects [19, 20, 21]. This review summarizes the current research on OS-related male infertility and the therapeutic potential of nanoantioxidants (nanoAOXs) in improving testicular function and sperm parameters.

2. Impact of OS on Spermatozoa

Approximately 30–80% of males who struggle with infertility issues are reported to have increased ROS levels in their seminal fluid [16]. Endogenous sources of ROS include leukocytes and abnormal/immature spermatozoa. Exogenous factors are more diverse and encompass environmental pollutants, radiation, infections, inflammation, male genital tract conditions such as varicocele and cryptorchidism, and lifestyle-related factors including tobacco and nicotine use (smoking and vaping), high-fat diets, and alcohol consumption [16, 22]. It is well known that spermatozoa produce ROS at two distinct sites—the sperm plasma membrane and the mitochondria—through the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system and the NADH-dependent oxidoreductase (diaphorase), respectively [23]. ROS, such as hydroxyl radicals, superoxide anion, and hydrogen peroxide, are mainly produced by mitochondria during the oxidative phosphorylation process [24]. Due to unique aspects of sperm structure, such as cell membranes enriched with PUFA [22] and a lack of protective antioxidants in sperm cytoplasm, they are very sensitive to OS. Additionally, the large surface area compared to the limited cytoplasm makes sperm more susceptible to damage. Spermatozoa membranes rich in PUFA could be damaged by ROS through lipid peroxidation (LPO) reactions, leading to the production of mutagenic molecules such as malondialdehyde (MDA) [25]. When in excess, ROS induce sperm DNA fragmentation (SDF) [26] and impair sperm maturation, thereby increasing the risk of recurrent pregnancy loss and preterm delivery [22]. The excessive accumulation of ROS affects sperm mitochondrial function, adenosine triphosphate (ATP) production, and sperm motility [22]. These intracellular changes affect proteins and molecular signaling pathways in sperm, resulting in programmed cell death and apoptosis [27, 28]. Infertile men show significantly elevated levels of apoptotic pathway indicators in their sperm.

Several factors can influence ROS production levels, including leukocyte activation from infection or inflammation, radiation exposure, and toxin exposure [16]. Excessive levels of ROS and reduced natural antioxidants lead to an imbalance, resulting in OS. The ATP outflow from cells and decreased viability can cause sperm morphological defects and impaired motility, which ultimately reduce sperm quality and fertility potential [29, 30]. Studies have shown that sperm lack cytoplasmic enzyme repair systems, leaving DNA damage unrepaired and chromatin poorly packaged, which increases apoptotic pathway activation [30, 31]. OS could increase the percentage of unrepaired single- or double-stranded DNA through direct or indirect pathways. The direct impact of OS on DNA bases is the formation of adducted 8-hydroxy-2-deoxyguanosine (8-OHdG), which eventually induces apoptotic pathways. The indirect effect of OS on DNA damage results in the production of MDA, a mutagenic byproduct of LPO [32]. It has also been demonstrated that reduced antioxidant levels can trigger excessive ROS production in semen [33]. For instance, Vit C or Zn deficiency results in increased SDF and male infertility [34, 35, 36].

3. Nanoparticles and Their Role in Alleviating OS

Poor bioavailability and low stability of conventional antioxidant formulations have driven the development of advanced drug delivery systems, such as nanoparticles (NPs), nanoemulsions, and liposomes [37]. These innovative systems could easily cross the blood-testis barrier, providing higher concentrations in targeted tissues [38] and ultimately improving drug efficacy with minimal toxicity [39]. Due to their size, shape, surface hydrophilicity or hydrophobicity, elasticity, and surface charge, NPs affect cellular uptake and pharmacokinetics of loaded drugs (e.g., antioxidants or hormones) and increase their efficacy even at lower doses [21, 40, 41]. Upon administration, NPs are absorbed through several pathways, including various forms of endocytosis (clathrin-mediated, caveolae-mediated, and caveolae-independent), cellular uptake processes (phagocytosis, pinocytosis, and micropinocytosis), and direct transport methods (passive diffusion, electroporation, and microinjection) [42, 43, 44]. The intracellular trafficking of NPs is pivotal in determining their ultimate target within cellular components [40] and therapeutic effects [44]. NPs, internalized through endocytosis, become enclosed within endosomes (membrane-lined vesicles) [44]. This trafficking is primarily governed by three types of endosomes (early, late, and recycling) and the Golgi apparatus [43]. The early endosome, which contains endocytosed material, partially fuses with the recycling endosome, while the remnant part is differentiated into the late endosome. This dynamic process is facilitated by cellular microtubules, which play a crucial role in enabling NPs to pass the cell-membrane-nuclei path [42, 43].

One of the antioxidant NP formulations recently investigated is cerium oxide nanoparticles (CeO₂NPs). Their increased surface area-to-volume and reversible transition between the two cationic forms of cerium (Ce³⁺ and Ce⁴⁺) effectively neutralize ROS, including hydroxyl and nitric oxide radicals [45, 46, 47]. Notably, this study investigates citrate-coated CeO₂NPs, which lead to significant accumulation of antioxidants in mitochondria without inducing an immune response [45]. Furthermore, some metallic NPs containing manganese (Mn), copper (Cu), or iron (Fe) can function like a superoxide dismutase (SOD) enzyme that neutralizes ROS through catalytic mechanisms [48, 49]. In addition, the evaluation of carboxymethyl inulin-coated iron oxide nanoparticles (Fe₂O₃NPs) has demonstrated high stability and targeted delivery [50]. Conjugated Vit C-NPs, including silica-coated gold (Au) NPs and polymeric micelles, have shown intracellular antioxidative activity at lower concentrations [51].

A substantial body of research has explored the effects of NPs on embryo culture, shedding light on their potential benefit for assisted reproductive technology (ART) [21]. Komninou et al. [52] assessed the effect of melatonin-loaded lipid-core nanocapsules in an in vitro bovine-cultured embryo. The results indicated lower levels of the proapoptotic BAX gene and apoptosis-related CASP3 gene but higher levels of the OS-related catalase (CAT) gene and superoxide dismutase 2 (SOD2) gene. These effects led to reduced OS and apoptotic cell death, ultimately improving embryo quality and indicating enhanced intracellular bioavailability of melatonin [52].

4. NanoAOX and Its Effect on Testicular Function, Spermatogenesis, and Semen Parameters

NPs, with their established capabilities in drug delivery, enhanced bioavailability, and reduced toxicity, represent a novel approach that has attracted considerable attention for their potential use in diagnosing and treating male infertility [53]. Based on their activity and chemical structure, antioxidants fall into two distinct categories, enzymatic and nonenzymatic antioxidants [54], which are present in both cellular and extracellular environments [55]. Enzymatic antioxidants, aided by trace elements like Zn, Fe, Mg, and Cu, facilitate the conversion of ROS into hydrogen peroxide, which is subsequently metabolized into water [55]. Several nonenzymatic antioxidants, like Vit C, Vit E, melatonin, curcumin, plant polyphenols, and reduced glutathione, work by neutralizing free radicals and stopping their chain reactions [56]. Although antioxidants play a crucial role in protecting cells from OS damage and show promise in treating male infertility, they have certain limitations. Low solubility and stability represent major limitations, resulting in variable bioavailability [57]. The utilization of nanoAOX enhances durability, increased cellular uptake, and targeted delivery [54].

Nanoencapsulated antioxidants are protected from gastrointestinal degradation, thereby improving bioavailability and therapeutic efficacy while reducing cytotoxic damage compared to nonencapsulated formulations. For example, increased active intracellular uptake of polymeric NPs in the small intestine results in enhanced targeted drug delivery [58]. A nanoencapsulated formulation of Vit C, for instance, can prolong the drug’s half-life [59]. Due to their antioxidative properties, NPs are beneficial to sperm function and may improve male infertility (Fig. 1) [19]. Various methods have been used to produce NP-containing antioxidants, including supercritical fluid technology, solvent displacement templating, emulsion/solvent evaporation, and nanoprecipitation [60]. The positive effects of nanoAOXs on male reproductive systems, as documented in animal studies, are presented in Table 1 (Ref. [61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83]).

4.1 Curcumin Nanoparticles

Curcumin nanoparticles (CurNPs) have shown beneficial effects on male fertility by enhancing various sperm parameters: count, concentration, motility, and morphology [84]. Furthermore, curcumin can potentially suppress OS and reduce tissue atrophy [85]. CurNPs demonstrated several beneficial effects, including reduced levels of ROS and LPO, decreased sperm DNA fragmentation, and improved testicular function in rats with varicocele-induced infertility [61]. Daily supplementation with CurNPs could improve reproductive performance and spermatogenesis in juvenile rats on a protein-deficient diet (PDD). Conversely, malnutrition and protein deficiency trigger excessive production of ROS and reactive nitrogen species. Methionine-deficient diets typically cause MDA levels to progressively increase while glutathione levels notably decrease, accompanied by significant reductions in CAT and SOD enzyme activities. The study also showed that a PDD resulted in a significant decrease in testes weight and sperm parameters such as total count and progressive motility. Biochemically, testicular tissue exhibited reduced adenylate energy charge, increased 8-OHdG levels, along with OS and nitrosative stress. Additionally, the study revealed a negative correlation between sperm concentration and progressive motility and several factors such as elevated 8-OHdG levels, increased OS, disrupted cell energy, and elevated amino acid (essential and nonessential) levels in seminal plasma. The findings indicated that CurNPs prevented the detrimental effects associated with PDD [62].

Exposure to Cu compounds has been linked to harmful effects on the pituitary-gonadal axis and steroidogenesis, including testicular OS, apoptosis, and diminished sperm quality [86, 87]. Both curcumin and liposomal CurNPs reduce testicular oxidative injury, inflammation, and apoptosis caused by copper sulfate (CuSO4) exposure in rats [63]. They also improved cell proliferation, normalized circulating sex hormone levels, and enhanced steroidogenesis. These protective effects were linked to activation of the nuclear factor erythroid 2-related factor/heme oxygenase-1 (Nrf2/HO-1) signaling pathway and an overall rise in antioxidant levels. Activation of Nrf2/HO-1 signaling has been shown to protect the testis from OS, inflammation, and apoptosis caused by heavy metals [88]. Notably, CurNPs provide stronger protection than curcumin alone, likely due to their improved properties.

4.2 Zinc Oxide Nanoparticles

Animal studies have shown that zinc oxide nanoparticles (ZnONPs) significantly reduce apoptosis, enhance spermatogonia, and reduce oxidative damage to the sperm cell membrane due to their potent antioxidant properties [66, 89]. Omu et al. [90] found that Zn deficiency was associated with elevated OS, as marked by increased LPO, caspase-3 activity, and tumor necrosis factor-alpha levels.

Mohamed and Abdelrahman [64] analyzed the harmful reproductive effects of cigarette smoke exposure and evaluated ZnONPs as a potential protective agent against nicotine-induced male reproductive dysfunction. Nicotine-exposed rats treated with ZnONPs showed reduced OS and increased expression of steroidogenic enzymes. Coadministration of nicotine and ZnONPs to rats led to the development of a thin connective tissue capsule with blood vessels and maintained the normal structural organization of the seminiferous tubules [64].

Research showed that aluminum chloride (AlCl₃) given orally to rats resulted in testicular oxidative damage, marked by elevated MDA and nitric oxide levels and reduced glutathione content and CAT activity. When these rats received daily intraperitoneal ZnONP injections prior to AlCl₃ exposure, the reproductive toxicity from AlCl₃ was significantly reduced. Furthermore, ZnONP treatment improved testicular inflammatory, apoptotic, and reproductive markers; corrected histopathological changes; and enhanced Ki-67 immunoreactivity in spermatogenic cells [65].

Dietary supplementation with ZnONPs enhanced epididymal semen quality, seminal antioxidant activity, and Cu-Zn SOD expression in young rams [66]. The addition of ZnONP to bull semen extender likewise decreased MDA levels while enhancing mitochondrial activity [67]. Additionally, ZnONPs dose-dependently improved sperm plasma membrane function while preserving motility characteristics [68].

4.3 Selenium Nanoparticles

Selenium nanoparticles (SeNPs) have a positive impact on semen quality through their antioxidant properties and ability to protect against OS. SeNPs are also reported to scavenge ROS and inhibit LPO [91, 92] to protect spermatozoa from oxidative damage [93]. SeNPs demonstrated superior efficacy compared to other Se forms (sodium selenite and selenized yeast) in enhancing antioxidant enzyme activity, including glutathione peroxidase (GPX), SOD, and CAT, while simultaneously improving sperm quality [69, 70, 94]. Hozyen et al. [71] conducted a study in which they orally administered SeNPs (0.5 mg/kg bwt) to male rats with deltamethrin-induced infertility. The results indicated improvements in sperm parameters as well as increased levels of antioxidants, GPX activity, and testosterone levels [71]. Likewise, multiple rat studies have demonstrated that SeNPs improve sperm parameters by reducing OS damage [72, 73, 74].

Research has shown that SeNP administration effectively counteracts the adverse effects of monosodium glutamate (MSG). Regardless of dosage, MSG administration resulted in significantly reduced testosterone levels and notably increased OS markers. Nevertheless, SeNPs provided effective protection against MSG-induced damage, demonstrating strong antioxidant activity that significantly boosted antioxidant enzyme levels and reduced MDA levels. These findings indicate that SeNPs protect against testicular injury while enhancing antioxidant status [75]. Additionally, Se enhances the testicular architecture and sprerm production by effectively scavenging ROS produced by MSG [75]. Through improved antioxidant capacity and reduced MDA levels, SeNPs effectively restored testosterone levels.

4.4 Manganese Dioxide Nanoparticles

Manganese dioxide nanoparticles (MnO₂NPs) possess antioxidant-mimicking properties and can inhibit apoptosis [95, 96]. Their antioxidant capacity is evident in their ability to boost endogenous antioxidant-enzyme levels and reduce the OS marker MDA. Microwave exposure triggers OS, which in turn affects reproductive parameters [97]. MnO₂NPs at 12.5 mg/kg protect the reproductive system against microwave-induced modifications [76]. As an antioxidant mimic, MnO₂NPs neutralize microwave-induced OS, protecting cells and tissues from further damage.

4.5 Iron Oxide Nanoparticles

Fe₂O₃NPs have strong potential owing to their superior drug-carrying capacity and enhanced targeting ability, which are derived from their magnetic and biological properties [98]. Fe₂O₃NPs, along with CoQ10, exhibited antioxidant properties and significantly improved semen parameters. This combination represents a promising therapeutic approach for addressing hyperthermia-induced scrotal damage and associated infertility [77]. Moreover, curcumin-coated Fe₂O₃NPs boosted testosterone levels, increased germ cell proliferation, and decreased apoptotic sperm cells in mice subjected to testicular hyperthermia [78].

4.6 Cerium Dioxide Nanoparticles

CeO₂NPs with their autocatalytic, antioxidant, and regenerative properties, stand out as exceptional therapeutic agents that target pathologies associated with chronic OS and inflammation [99, 100]. CeO₂NPs, known for their antioxidant, autoregenerative, and low-toxicity properties, have shown promising therapeutic results for male health and fertility [45, 101, 102]. Recent findings reveal that CeO₂NPs function as antioxidant agents by scavenging hydroxyl and nitric oxide radicals and mimicking SOD and CAT activity [103, 104] and CAT mimetic activity [105]. Karakoti et al. [106] demonstrated that CeO₂NPs can efficiently neutralize superoxide, a harmful metabolic byproduct of the cell. The antioxidative capabilities of CeO₂NPs hold significant potential for positively impacting the progression of male infertility [45].

Oral administration of CeO₂NPs (1 mg/kg, single dose) resulted in accelerated spermatogenesis in reproductively active male rats. Further, CeO₂NPs, even at a higher dose (100 mg/kg), did not significantly affect either sperm parameters or the structural-functional integrity of the reproductive system [107]. A 10-day regimen of CeO₂NPs led to increased sperm count and improved quantitative sperm parameters. It also significantly lowered serum LPO levels while boosting CAT and SOD activity [45]. Moridi et al. [79] divided 36 male Wistar rats into six groups and treated them with different concentrations of CeO₂NPs, malathion, or CeO₂NPs + malathion. Administration of CeO₂NPs remarkably enhanced testicular sperm viability compared to the malathion-treated group. Additionally, sperm parameters were notably improved in the rats coadministered with CeO₂NPs and malathion, which demonstrates the protective effect of CeO₂NPs against malathion-induced toxicity in the rat testis. Further, the CeO₂NPs- administered group exhibited higher total antioxidant capacity and thiol levels than the malathion-exposed group. CeO₂NPs mimic the properties of the SOD enzyme, effectively reducing testicular MDA levels at both 15 mg/kg and 30 mg/kg dosages, with the latter showing statistically notable improvement [79].

4.7 Nano Vitamins

Vitamin deficiencies, particularly of Vit C, B1, and B6, have been linked to increased risk of cadmium and lead (Pb) toxicity [108]. Vitamin supplementation is important to protect against free radical damage, which effectively prevents LPO in organs. For instance, the protective effects of Vit C on the liver, kidneys, brain, and testes against oxidative damage induced by Pb exposure have been shown. Exposure to arsenic and Pb triggers OS, apoptosis, and cytotoxicity, which can ultimately cause male infertility [80]. Vit C-NPs and other antioxidant complexes act as therapeutic agents against spermatogenic toxicity by targeting apoptosis-inducing gene expression. Chakraborty and Jana [51] demonstrated that NPs (polyaspartimide and Au) conjugated with Vit C provide protection against OS. Male rats supplemented with Vit C-NPs showed improved sperm parameters, increased testosterone, LH and FSH levels, and enhanced antioxidant enzyme (GPX, SOD, CAT) activity. In another study, Jurado-Campos et al. [81] reported that treatment with Vit E nanoemulsion significantly reduced ROS production and LPO levels under OS conditions in ram sperm. Similar effects have been observed in studies involving bull [109, 110], boar [111], and human [112] sperm.

Nanoemulsion of Vit E demonstrated a protective effect by lowering ROS and LPO levels and reducing DNA fragmentation. Additionally, it enhanced sperm viability and preserved mitochondrial activity in red deer spermatozoa [82]. Sánchez-Rubio et al. [83] observed the protective effects of Vit E nanoemulsions against OS using red deer epididymal sperm. These nanoemulsions enhanced motility parameters such as progressivity and sperm velocity while preserving mitochondrial activity. They effectively reduced ROS production, prevented LPO following OS, and safeguarded the integrity of the acrosome, thereby preventing cell death [83].

5. The Role of NanoAOX or NPs in Treating Diabetic-Induced Male Infertility

ROS generation is one of the most common consequences of diabetes mellitus [113]. Diabetes mellitus directly impacts male fertility by inducing OS, with a subfertility prevalence rate of 51% among diabetic patients [114]. It is well established that diabetes mellitus leads to adverse changes in sperm count, quality, and function [115]. Furthermore, diabetes mellitus negatively affects male fertility at multiple levels, including ejaculation, endocrine regulation of spermatogenesis, erection, semen volume, as well as sperm vitality and motility [116].

ZnONPs have been reported to increase sperm parameters and function by mitigating OS in diabetic rats [117]. Further, ZnONPs offer a safer therapeutic option for diabetic male rats, providing OS protection through antioxidant and anti-inflammatory mechanisms while maintaining low toxicity profiles [118].

6. Utilization of NanoAOX or NPs in Semen Cryopreservation

Sperm banking is a well-established method for preserving fertility [119]. Sperm cryopreservation has also become a promising solution for addressing many male infertility issues. Over the past five decades, various methods for sperm freezing have been developed, making it an integral component of ART [120]. Semen cryopreservation has a negative impact on sperm parameters such as motility, morphology, viability, and DNA integrity [121] and can increase ROS generation in spermatozoa, substantially reducing their fertilization potential [122]. Spermatozoa as such is vulnerable to free radical attacks. Their plasma membranes are rich in unsaturated fatty acids, while their minimal cytoplasm provides limited free-radical scavenging capacity [123]. Animal studies reporting the positive effects of nanoAOX in semen cryopreservation are summarized in Table 2 (Ref. [121, 124, 125, 126, 127, 128]).

SeNPs have shown promising results in mitigating OS during cryopreservation. Safa et al. [124] demonstrated that semen enrichment with SeNPs and Vit E increased antioxidant levels in seminal plasma of roosters and potentially humans, by reducing LPO after freeze-thaw cycles. NP forms (Vit E-NPs and SeNPs) were more effective than conventional Se and Vit E in maintaining sperm quality and morphology [124]. Furthermore, both SeNPs and ZnONPs protected cryopreserved spermatozoa by reducing apoptosis and improving sperm quality [125, 129].

CeO₂NPs have been studied for their ability to retain oxygen and serve as ROS scavengers, protecting the viability of ram sperm cells during the cryopreservation process [130]. CeO₂NPs possess antioxidant properties that can alleviate OS during the cryopreservation process and enhance the activity of antioxidant enzymes. Particularly, adding 25 and 50 µg/mL CeO₂NPs improved motility velocity, viability, plasma membrane, acrosome, and DNA integrity of sperm [126].

Elshamy et al. [121] evaluated the effectiveness of cupric oxide nanoparticles (CuONPs) when used as cryo-extender additives in preserving sperm quality after thawing. The results indicated that seminal plasma removal prior to cryopreservation had detrimental effects on sperm parameters. CuONPs supplementation provided broad-spectrum improvements in sperm function (motility, viability), cellular integrity (membrane, DNA), and antioxidant status (biochemical markers, reduced MDA). Seminal plasma enriched with high CuONPs concentrations apparently reduces the negative impact of cryopreservation on sperm quality [121].

Fe₂O₃NPs coated with anti-ubiquitin antibodies were used to deplete dead/damaged spermatozoa in freshly ejaculated semen. Nano-purified semen samples that were treated with Fe₂O₃NPs (2.0 µg/mL) conjugated to anti-ubiquitin antibodies improved sperm DNA integrity by removing dead or damaged spermatozoa in buffalo ejaculates, serving as a promising approach to reduce OS and enhance post-thaw semen quality [127].

Studies have demonstrated that ZnONPs significantly reduce MDA levels, indicating that these NPs effectively scavenge free radicals generated during the freeze-thaw process and protect spermatozoa from oxidative damage [128, 131]. Nano-vitamins showed protection against LPO in cryopreserved semen, with possible implications in the field of ART [21]. Jurado-Campos et al. [132] utilized a Vit E nanoemulsion to preserve ram sperm, supporting the use of nano-controlled-release antioxidants to prevent OS in an ART setting.

7. The Effect of NanoAOX on Radiation and Chemotherapeutic Agents

Utilizing cytotoxic chemotherapies for the treatment of malignancies can cause long-term gonadotoxicity and Leydig cell impairment. These negative effects, which depend on the dose and type of chemotherapy agent, can impact male reproductive health, specifically testicular function. Animal studies reporting the positive effects of nanoAOX on radiation and chemotherapeutic agents are summarized in Table 3 (Ref. [133, 134, 135, 136, 137, 138]).

A study of adult Wistar rats confirmed that doxorubicin triggers LPO, as evidenced by increased levels of MDA. Doxorubicin readily autoxidizes in the presence of oxygen, producing superoxide and other ROS, thereby stimulating LPO [119]. The findings indicated that doxorubicin-induced reproductive toxicity is associated with heightened OS.

Treatment with ZnONPs ameliorated doxorubicin-induced male gonadotoxicity by attenuating OS through their antioxidant activity [133]. ZnONPs also exhibit anti-apoptotic effects in cyclophosphamide-induced testicular damage in male rats via suppression of caspase expression or improvement of mitochondrial function. This leads to reduced levels of cytochrome c and apoptosis-inducing factors, which act as intrinsic cellular death signals [134]. ZnONPs also exhibit potent antioxidant activity, effectively preventing both testicular tissue changes and the decrease in spermatogenic cell numbers resulting from cyclophosphamide treatment [135].

Cisplatin, an anticancer drug with male reproductive toxicity, causes significant reproductive damage. Oral SeNPs administration was able to restore spermatogenesis, improve sperm quality (motility and DNA integrity), and mitigate oxidative damage [136]. AuNPs synthesized utilizing Nasturtium officinale (AuNPs-NO) showed significant cytoprotective and antioxidant properties against cyclophosphamide-induced testicular damage in rats, effectively preventing spermatogenic apoptosis [137]. Magnesium hydride (MgH₂), a hydrogen-storage nanomaterial, provides protective effects by suppressing inflammation, apoptosis, and pyroptosis and by alleviating cell cycle arrest caused by irradiation. Under in vitro conditions, MgH₂ also reduces MDA levels via dual mechanisms: inhibition of ROS generation and elimination of hydroxyl radical (^.OH) through H₂ production [138].

8. Personalized Treatment With NPs in the Management of Male Infertility

Disease characteristics and treatment responses differ among patients due to factors such as genetics, phenotype, blood hemostasis, physiological stress, lifestyle habits, and environmental conditions [139, 140]. These variations lead to the development of a novel delivery system, assuring higher efficacy and treatment safety [140]. NPs, with their unique features, such as a higher surface-to-volume ratio due to their small particle size, compatibility with formulating drugs that have poor bioavailability, and the ability for controlled and targeted delivery, present a promising approach to treatment [139]. Personalized treatment, with the help of omics sciences, including genomics, transcriptomics, proteomics, and metabolomics, reveals information about the genetic profile of infertility development. Genetic factors influencing nutrition metabolism can impact the antioxidant status and fertility chance. Determining exact genetic factors related to nutrition could enable personalized antioxidant supplementation for managing male infertility [141]. One approach for customized treatment involves utilizing nanocarrier functions activated by individuals’ intracellular enzymes. However, NP-mediated personalized treatment also faces challenges, such as potential nanocarrier toxicity, increased clearance time of loaded medicine, uncertainty about biodistribution, stability and storage complexities, regulatory approval difficulties, and economic concerns [142].

While the current findings provide promising insights based on preclinical studies, the translation of these results to human applications remains uncertain. To date, no large-scale clinical trials have been conducted to confirm the safety, efficacy, and pharmacokinetics of this approach in humans. Bridging this gap requires careful consideration of species differences, appropriate dosing strategies, and long-term safety profiles. Additionally, regulatory hurdles, including compliance with guidelines set by agencies such as the United States Food and Drug Administration or the European Medicines Agency, must be addressed before clinical implementation. Future studies should prioritize human-based investigations to validate the therapeutic potential and ensure successful clinical translation.

9. Conclusions

The management of male infertility associated with OS presents a significant challenge, requiring innovative approaches to improve treatment outcomes. Antioxidants have emerged as promising agents for mitigating OS and improving semen quality and sperm function. In this regard, the advent of nanotechnology has opened new opportunities for enhancing the effectiveness of antioxidant therapy in male infertility. NanoAOXs, characterized by enhanced durability, cellular uptake, and targeted delivery, can more effectively neutralize ROS and reduce OS damage in sperm cells. Additionally, nanoAOXs offer improved bioavailability and stability compared to conventional antioxidants, enhancing their therapeutic potential in managing male infertility. While traditional antioxidant therapy remains a valuable option in male infertility management, nanoAOXs offer a more potent and targeted approach. Their ability to overcome the limitations of conventional antioxidants and optimize treatment outcomes highlights their potential as a foundation of future infertility treatments. Further exploration and advancements in nanoAOX therapy offer hope for enhancing reproductive outcomes with reduced failures and addressing the complex issues of male infertility linked to OS.

References

[1] Zegers-Hochschild F, Adamson GD, de Mouzon J, Ishihara O, Mansour R, Nygren K, et al. International Committee for Monitoring Assisted Reproductive Technology (ICMART) and the World Health Organization (WHO) revised glossary of ART terminology, 2009. Fertility and Sterility. 2009; 92: 1520–1524. https://doi.org/10.1016/j.fertnstert.2009.09.009.

[2] Schlegel PN, Sigman M, Collura B, De Jonge CJ, Eisenberg ML, Lamb DJ, et al. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline Part I. The Journal of Urology. 2021; 205: 36–43. https://doi.org/10.1097/JU.0000000000001521.

[3] Walker MH, Tobler KJ. Female Infertility. StatPearls: Treasure Island (FL). 2023.

[4] Harris E. Infertility Affects 1 in 6 People Globally. JAMA. 2023; 329: 1443. https://doi.org/10.1001/jama.2023.6251.

[5] Boivin J, Bunting L, Collins JA, Nygren KG. International estimates of infertility prevalence and treatment-seeking: potential need and demand for infertility medical care. Human Reproduction. 2007; 22: 1506–1512. https://doi.org/10.1093/humrep/dem046.

[6] Chandra A, Copen CE, Stephen EH. Infertility and impaired fecundity in the United States, 1982-2010: data from the National Survey of Family Growth. National Health Statistics Reports. 2013; 1–18.

[7] Vander Borght M, Wyns C. Fertility and infertility: Definition and epidemiology. Clinical Biochemistry. 2018; 62: 2–10. https://doi.org/10.1016/j.clinbiochem.2018.03.012.

[8] Durairajanayagam D. Lifestyle causes of male infertility. Arab Journal of Urology. 2018; 16: 10–20. https://doi.org/10.1016/j.aju.2017.12.004.

[9] Kumar N, Singh AK. Impact of environmental factors on human semen quality and male fertility: a narrative review. Environmental Sciences Europe. 2022; 34: 1–13. https://doi.org/10.1186/s12302-021-00585-w.

[10] Ferlin A, Raicu F, Gatta V, Zuccarello D, Palka G, Foresta C. Male infertility: role of genetic background. Reproductive Biomedicine Online. 2007; 14: 734–745. https://doi.org/10.1016/s1472-6483(10)60677-3.

[11] Sharma M, Leslie SW. Azoospermia. StatPearls: Treasure Island (FL). 2023.

[12] Agarwal A, Majzoub A, Parekh N, Henkel R. A Schematic Overview of the Current Status of Male Infertility Practice. The World Journal of Men’s Health. 2020;38: 308–322. https://doi.org/10.5534/wjmh.190068.

[13] Mittal PK, Little B, Harri PA, Miller FH, Alexander LF, Kalb B, et al. Role of Imaging in the Evaluation of Male Infertility. Radiographics. 2017; 37: 837–854. https://doi.org/10.1148/rg.2017160125.

[14] Ramalingam M, Kini S, Mahmood T. Male fertility and infertility. Obstetrics, Gynaecology & Reproductive Medicine. 2014; 24: 326–332. https://doi.org/10.1016/j.ogrm.2014.08.006.

[15] Agarwal A, Finelli R, Selvam MKP, Leisegang K, Majzoub A, Tadros N, et al. A Global Survey of Reproductive Specialists to Determine the Clinical Utility of Oxidative Stress Testing and Antioxidant Use in Male Infertility. The World Journal of Men’s Health. 2021; 39: 470–488. https://doi.org/10.5534/wjmh.210025.

[16] Pavuluri H, Bakhtiary Z, Panner Selvam MK, Hellstrom WJG. Oxidative Stress-Associated Male Infertility: Current Diagnostic and Therapeutic Approaches. Medicina. 2024; 60: 1008. https://doi.org/10.3390/medicina60061008.

[17] Salvio G, Cutini M, Ciarloni A, Giovannini L, Perrone M, Balercia G. Coenzyme Q10 and Male Infertility: A Systematic Review. Antioxidants. 2021; 10: 874. https://doi.org/10.3390/antiox10060874.

[18] Agarwal A, Leisegang K, Majzoub A, Henkel R, Finelli R, Panner Selvam MK, et al. Utility of Antioxidants in the Treatment of Male Infertility: Clinical Guidelines Based on a Systematic Review and Analysis of Evidence. The World Journal of Men’s Health. 2021; 39: 233–290. https://doi.org/10.5534/wjmh.200196.

[19] Falchi L, Khalil WA, Hassan M, Marei WFA. Perspectives of nanotechnology in male fertility and sperm function. International Journal of Veterinary Science and Medicine. 2018; 6: 265–269. https://doi.org/10.1016/j.ijvsm.2018.09.001.

[20] Patra JK, Das G, Fraceto LF, Campos EVR, Rodriguez-Torres MDP, Acosta-Torres LS, et al. Nano based drug delivery systems: recent developments and future prospects. Journal of Nanobiotechnology. 2018; 16: 71. https://doi.org/10.1186/s12951-018-0392-8.

[21] Silva JRV, Barroso PAA, Nascimento DR, Figueira CS, Azevedo VAN, Silva BR, et al. Benefits and challenges of nanomaterials in assisted reproductive technologies. Molecular Reproduction and Development. 2021; 88: 707–717. https://doi.org/10.1002/mrd.23536.

[22] Ritchie C, Ko EY. Oxidative stress in the pathophysiology of male infertility. Andrologia. 2021; 53: e13581. https://doi.org/10.1111/and.13581.

[23] Agarwal A, Saleh RA, Bedaiwy MA. Role of reactive oxygen species in the pathophysiology of human reproduction. Fertility and Sterility. 2003; 79: 829–843. https://doi.org/10.1016/s0015-0282(02)04948-8.

[24] Gharagozloo P, Aitken RJ. The role of sperm oxidative stress in male infertility and the significance of oral antioxidant therapy. Human Reproduction. 2011; 26: 1628–1640. https://doi.org/10.1093/humrep/der132.

[25] Nowicka-Bauer K, Nixon B. Molecular Changes Induced by Oxidative Stress that Impair Human Sperm Motility. Antioxidants. 2020; 9: 134. https://doi.org/10.3390/antiox9020134.

[26] Panner Selvam MK, Baskaran S, O’Connell S, Almajed W, Hellstrom WJG, Sikka SC. Association between Seminal Oxidation-Reduction Potential and Sperm DNA Fragmentation-A Meta-Analysis. Antioxidants. 2022; 11: 1563. https://doi.org/10.3390/antiox11081563.

[27] Ayad B, Omolaoye TS, Louw N, Ramsunder Y, Skosana BT, Oyeipo PI, et al. Oxidative Stress and Male Infertility: Evidence From a Research Perspective. Frontiers in Reproductive Health. 2022; 4: 822257. https://doi.org/10.3389/frph.2022.822257.

[28] Panner Selvam MK, Durairajanayagam D, Sikka SC. Kesari KK, Roychoudhury S. Molecular Interactions Associated with Oxidative Stress-Mediated Male Infertility: Sperm and Seminal Plasma Proteomics. In Oxidative Stress and Toxicity in Reproductive Biology and Medicine: A Comprehensive Update on Male Infertility- Volume One (pp. 63–76). Springer International Publishing: Cham. 2022. https://doi.org/10.1007/978-3-030-89340-8_4.

[29] Kurkowska W, Bogacz A, Janiszewska M, Gabryś E, Tiszler M, Bellanti F, et al. Oxidative Stress is Associated with Reduced Sperm Motility in Normal Semen. American Journal of Men’s Health. 2020; 14: 1557988320939731. https://doi.org/10.1177/1557988320939731.

[30] Mannucci A, Argento FR, Fini E, Coccia ME, Taddei N, Becatti M, et al. The Impact of Oxidative Stress in Male Infertility. Frontiers in Molecular Biosciences. 2022; 8: 799294. https://doi.org/10.3389/fmolb.2021.799294.

[31] Aitken RJ, Smith TB, Jobling MS, Baker MA, De Iuliis GN. Oxidative stress and male reproductive health. Asian Journal of Andrology. 2014; 16: 31–38. https://doi.org/10.4103/1008-682X.122203.

[32] Agarwal A, Majzoub A, Baskaran S, Panner Selvam MK, Cho CL, Henkel R, et al. Sperm DNA Fragmentation: A New Guideline for Clinicians. The World Journal of Men’s Health. 2020; 38: 412–471. https://doi.org/10.5534/wjmh.200128.

[33] Aitken RJ, Drevet JR, Moazamian A, Gharagozloo P. Male Infertility and Oxidative Stress: A Focus on the Underlying Mechanisms. Antioxidants. 2022; 11: 306. https://doi.org/10.3390/antiox11020306.

[34] Fraga CG, Motchnik PA, Shigenaga MK, Helbock HJ, Jacob RA, Ames BN. Ascorbic acid protects against endogenous oxidative DNA damage in human sperm. Proceedings of the National Academy of Sciences of the United States of America. 1991; 88: 11003–11006. https://doi.org/10.1073/pnas.88.24.11003.

[35] Zhao Y, Zhao H, Zhai X, Dai J, Jiang X, Wang G, et al. Effects of Zn deficiency, antioxidants, and low-dose radiation on diabetic oxidative damage and cell death in the testis. Toxicology Mechanisms and Methods. 2013; 23: 42–47. https://doi.org/10.3109/15376516.2012.731437.

[36] Omu AE, Al-Azemi MK, Kehinde EO, Anim JT, Oriowo MA, Mathew TC. Indications of the mechanisms involved in improved sperm parameters by zinc therapy. Medical Principles and Practice: International Journal of the Kuwait University, Health Science Centre. 2008; 17: 108–116. https://doi.org/10.1159/000112963.

[37] Rahman HS, Othman HH, Hammadi NI, Yeap SK, Amin KM, Abdul Samad N, et al. Novel Drug Delivery Systems for Loading of Natural Plant Extracts and Their Biomedical Applications. International Journal of Nanomedicine. 2020; 15: 2439–2483. https://doi.org/10.2147/IJN.S227805.

[38] Alfaro Gómez M, Fernández-Santos MDR, Jurado-Campos A, Soria-Meneses PJ, Montoro Angulo V, Soler AJ, et al. On Males, Antioxidants and Infertility (MOXI): Certitudes, Uncertainties and Trends. Antioxidants. 2023; 12: 1626. https://doi.org/10.3390/antiox12081626.

[39] Fraser B, Peters AE, Sutherland JM, Liang M, Rebourcet D, Nixon B, et al. Biocompatible Nanomaterials as an Emerging Technology in Reproductive Health; a Focus on the Male. Frontiers in Physiology. 2021; 12: 753686. https://doi.org/10.3389/fphys.2021.753686.

[40] Foroozandeh P, Aziz AA. Insight into Cellular Uptake and Intracellular Trafficking of Nanoparticles. Nanoscale Research Letters. 2018; 13: 339. https://doi.org/10.1186/s11671-018-2728-6.

[41] Augustine R, Hasan A, Primavera R, Wilson RJ, Thakor AS, Kevadiya BD. Cellular uptake and retention of nanoparticles: Insights on particle properties and interaction with cellular components. Materials Today Communications. 2020; 25: 101692. https://doi.org/10.1016/j.mtcomm.2020.101692.

[42] Panariti A, Miserocchi G, Rivolta I. The effect of nanoparticle uptake on cellular behavior: disrupting or enabling functions? Nanotechnology, Science and Applications. 2012; 5: 87–100. https://doi.org/10.2147/NSA.S25515.

[43] Behzadi S, Serpooshan V, Tao W, Hamaly MA, Alkawareek MY, Dreaden EC, et al. Cellular uptake of nanoparticles: journey inside the cell. Chemical Society Reviews. 2017; 46: 4218–4244. https://doi.org/10.1039/c6cs00636a.

[44] Donahue ND, Acar H, Wilhelm S. Concepts of nanoparticle cellular uptake, intracellular trafficking, and kinetics in nanomedicine. Advanced Drug Delivery Reviews. 2019; 143: 68–96. https://doi.org/10.1016/j.addr.2019.04.008.

[45] Kobyliak NM, Falalyeyeva TM, Kuryk OG, Beregova TV, Bodnar PM, Zholobak NM, et al. Antioxidative effects of cerium dioxide nanoparticles ameliorate age-related male infertility: optimistic results in rats and the review of clinical clues for integrative concept of men health and fertility. The EPMA Journal. 2015; 6: 12. https://doi.org/10.1186/s13167-015-0034-2.

[46] Xue Y, Luan Q, Yang D, Yao X, Zhou K. Direct evidence for hydroxyl radical scavenging activity of cerium oxide nanoparticles. The Journal of Physical Chemistry C. 2011; 115: 4433–4438. https://doi.org/10.1021/jp109819u.

[47] Dowding JM, Dosani T, Kumar A, Seal S, Self WT. Cerium oxide nanoparticles scavenge nitric oxide radical (˙NO). Chemical Communications. 2012; 48: 4896–4898. https://doi.org/10.1039/c2cc30485f.

[48] Liu Y, Shi J. Antioxidative nanomaterials and biomedical applications. Nano Today. 2019; 27: 146–177. https://doi.org/10.1016/j.nantod.2019.05.008.

[49] Shen X, Liu W, Gao X, Lu Z, Wu X, Gao X. Mechanisms of Oxidase and Superoxide Dismutation-like Activities of Gold, Silver, Platinum, and Palladium, and Their Alloys: A General Way to the Activation of Molecular Oxygen. Journal of the American Chemical Society. 2015; 137: 15882–15891. https://doi.org/10.1021/jacs.5b10346.

[50] Santiago-Rodríguez L, Lafontaine MM, Castro C, Méndez-Vega J, Latorre-Esteves M, Juan EJ, et al. Synthesis, Stability, Cellular Uptake, and Blood Circulation Time of Carboxymethyl-Inulin Coated Magnetic Nanoparticles. Journal of Materials Chemistry. B. 2013; 1: 2807–2817. https://doi.org/10.1039/C3TB20256A.

[51] Chakraborty A, Jana NR. Vitamin C-Conjugated Nanoparticle Protects Cells from Oxidative Stress at Low Doses but Induces Oxidative Stress and Cell Death at High Doses. ACS Applied Materials & Interfaces. 2017; 9: 41807–41817. https://doi.org/10.1021/acsami.7b16055.

[52] Komninou ER, Remião MH, Lucas CG, Domingues WB, Basso AC, Jornada DS, et al. Effects of Two Types of Melatonin-Loaded Nanocapsules with Distinct Supramolecular Structures: Polymeric (NC) and Lipid-Core Nanocapsules (LNC) on Bovine Embryo Culture Model. PLoS ONE. 2016; 11: e0157561. https://doi.org/10.1371/journal.pone.0157561.

[53] Barroso PAA, Nascimento DR, Lima Neto MFD, De Assis EIT, Figueira CS, Silva JRV. Therapeutic potential of nanotechnology in reproduction disorders and possible limitations. Zygote. 2023; 31: 433–440. https://doi.org/10.1017/S0967199423000424.

[54] Taouzinet L, Fatmi S, Lahiani-Skiba M, Skiba M, Iguer-Ouada M. Encapsulation Nanotechnology in Sperm Cryopreservation: Systems Preparation Methods and Antioxidants Enhanced Delivery. Cryo Letters. 2021; 42: 1–12.

[55] Nimse SB, Pal D. Free radicals, natural antioxidants, and their reaction mechanisms. RSC Advances. 2015; 5: 27986–28006. https://doi.org/10.1039/C4RA13315C.

[56] Moussa Z, Judeh Z, Ahmed SA. Nonenzymatic exogenous and endogenous antioxidants. Free Radical Medicine and Biology. 2019; 1: 11–22.

[57] Eftekhari A, Dizaj SM, Chodari L, Sunar S, Hasanzadeh A, Ahmadian E, et al. The promising future of nano-antioxidant therapy against environmental pollutants induced-toxicities. Biomedicine & Pharmacotherapy. 2018; 103: 1018–1027. https://doi.org/10.1016/j.biopha.2018.04.126.

[58] Müller RH, Mäder K, Gohla S. Solid lipid nanoparticles (SLN) for controlled drug delivery - a review of the state of the art. European Journal of Pharmaceutics and Biopharmaceutics. 2000; 50: 161–177. https://doi.org/10.1016/s0939-6411(00)00087-4.

[59] Bedhiafi T, Idoudi S, Fernandes Q, Al-Zaidan L, Uddin S, Dermime S, et al. Nano-vitamin C: A promising candidate for therapeutic applications. Biomedicine & Pharmacotherapy. 2023; 158: 114093. https://doi.org/10.1016/j.biopha.2022.114093.

[60] Tijjani H, Olatunde A, Zangoma MH, Egbuna C, Danyaro AM, Abdulkarim H, et al. Nanoformulation of antioxidant supplements. In Applications of Nanotechnology in Drug Discovery and Delivery (pp. 45–70). Elsevier: Amsterdam, Netherlands. 2022.

[61] Sadraei MR, Tavalaee M, Forouzanfar M, Nasr-Esfahani MH. Effect of curcumin, and nano-curcumin on sperm function in varicocele rat model. Andrologia. 2022; 54: e14282. https://doi.org/10.1111/and.14282.

[62] Ahmed-Farid OAH, Nasr M, Ahmed RF, Bakeer RM. Beneficial effects of curcumin nano-emulsion on spermatogenesis and reproductive performance in male rats under protein deficient diet model: enhancement of sperm motility, conservancy of testicular tissue integrity, cell energy and seminal plasma amino acids content. Journal of Biomedical Science. 2017; 24: 66. https://doi.org/10.1186/s12929-017-0373-5.

[63] Sarawi WS, Alhusaini AM, Fadda LM, Alomar HA, Albaker AB, Alghibiwi HK, et al. Nano-Curcumin Prevents Copper Reproductive Toxicity by Attenuating Oxidative Stress and Inflammation and Improving Nrf2/HO-1 Signaling and Pituitary-Gonadal Axis in Male Rats. Toxics. 2022; 10: 356. https://doi.org/10.3390/toxics10070356.

[64] Mohamed DA, Abdelrahman SA. The possible protective role of zinc oxide nanoparticles (ZnONPs) on testicular and epididymal structure and sperm parameters in nicotine-treated adult rats (a histological and biochemical study). Cell and Tissue Research. 2019; 375: 543–558. https://doi.org/10.1007/s00441-018-2909-8.

[65] Lokman M, Ashraf E, Kassab RB, Abdel Moneim AE, El-Yamany NA. Aluminum Chloride-Induced Reproductive Toxicity in Rats: the Protective Role of Zinc Oxide Nanoparticles. Biological Trace Element Research. 2022; 200: 4035–4044. https://doi.org/10.1007/s12011-021-03010-8.

[66] Zhang C, Qin X, Guo L, Zhang G, Zhang J, Ren Y. Effect of different Nano-zinc levels in dietary on semen quality, activities of antioxidant enzyme and expression of copper zinc superoxide in epididymis of ram lambs. Scientia Agricultura Sinica. 2015; 48: 154–164.

[67] Yazdanshenas P, Jahanbin R, Mohammadi Sangcheshmeh A, Aminafshar M, Vaseghi Dodaran H, Varnaseri H, et al. Effect of zinc nano-complex on bull semen quality and pregnancy outcome. Journal of Animal Production. 2016; 18: 173–181. https://doi.org/10.22059/jap.2016.54598.

[68] Jahanbin R, Yazdanshenas P, Amin Afshar M, Mohammadi Sangcheshmeh A, Varnaseri H, Chamani M, et al. Effect of zinc nano-complex on bull semen quality after freeze-thawing process. Journal of Animal Production. 2015; 17: 371–380. https://doi.org/10.22059/jap.2015.54040.

[69] Shi LG, Yang RJ, Yue WB, Xun WJ, Zhang CX, Ren YS, et al. Effect of elemental nano-selenium on semen quality, glutathione peroxidase activity, and testis ultrastructure in male Boer goats. Animal Reproduction Science. 2010; 118: 248–254. https://doi.org/10.1016/j.anireprosci.2009.10.003.

[70] Shi L, Xun W, Yue W, Zhang C, Ren Y, Shi L, et al. Effect of sodium selenite, Se-yeast and nano-elemental selenium on growth performance, Se concentration and antioxidant status in growing male goats. Small Ruminant Research. 2011; 96: 49–52. https://doi.org/10.1016/j.smallrumres.2010.11.005.

[71] Hozyen HF, Khalil HMA, Ghandour RA, Al-Mokaddem AK, Amer MS, Azouz RA. Nano selenium protects against deltamethrin-induced reproductive toxicity in male rats. Toxicology and Applied Pharmacology. 2020; 408: 115274. https://doi.org/10.1016/j.taap.2020.115274.

[72] Asadpour R, Aliyoldashi MH, Saberivand A, Hamidian G, Hejazi M. Ameliorative effect of selenium nanoparticles on the structure and function of testis and in vitro embryo development in Aflatoxin B1-exposed male mice. Andrologia. 2020; 52: e13824. https://doi.org/10.1111/and.13824.

[73] Khalaf AA, Ahmed W, Moselhy WA, Abdel-Halim BR, Ibrahim MA. Protective effects of selenium and nano-selenium on bisphenol-induced reproductive toxicity in male rats. Human & Experimental Toxicology. 2019; 38: 398–408. https://doi.org/10.1177/0960327118816134.

[74] Zhang X, Gan X, E Q, Zhang Q, Ye Y, Cai Y, et al. Ameliorative effects of nano-selenium against NiSO₄-induced apoptosis in rat testes. Toxicology Mechanisms and Methods. 2019; 29: 467–477. https://doi.org/10.1080/15376516.2019.1611979.

[75] Alrashidi MS, Gomaa HF. Testicular Effect of Selenium Nanoparticles on Monosodium Glutamate Induced Alteration in Male Albino Rats. Pakistan Journal of Biological Sciences : PJBS. 2023; 26: 347–359. https://doi.org/10.3923/pjbs.2023.347.359.

[76] Pardhiya S, Gautam R, Nirala JP, Murmu NN, Rajamani P. Modulatory role of Bovine serum albumin conjugated manganese dioxide nanoparticle on microwave radiation induced alterations in reproductive parameters of rat. Reproductive Toxicology. 2022; 113: 136–149. https://doi.org/10.1016/j.reprotox.2022.09.003.

[77] Paskeh MDA, Babaei N, Entezari M, Hashemi M, Doosti A. Protective Effects of Coenzyme Q10 Along with Fe₂O₃ Nanoparticles On Sperm Parameters in Rats with Scrotal Hyperthermia: Effects of CoQ 10 and Fe₂O₃ Nanoparticles On Sperm Parameters. Galen Medical Journal. 2022; 11: 1–7. https://doi.org/10.31661/gmj.v11i.2046.

[78] Afshar A, Aliaghaei A, Nazarian H, Abbaszadeh HA, Naserzadeh P, Fathabadi FF, et al. Curcumin-Loaded Iron Particle Improvement of Spermatogenesis in Azoospermic Mouse Induced by Long-Term Scrotal Hyperthermia. Reproductive Sciences. 2021; 28: 371–380. https://doi.org/10.1007/s43032-020-00288-2.

[79] Moridi H, Hosseini SA, Shateri H, Kheiripour N, Kaki A, Hatami M, et al. Protective effect of cerium oxide nanoparticle on sperm quality and oxidative damage in malathion-induced testicular toxicity in rats: An experimental study. International Journal of Reproductive Biomedicine. 2018; 16: 261–266.

[80] Raeeszadeh M, Karimfar B, Amiri AA, Akbari A. Protective effect of nano-vitamin C on infertility due to oxidative stress induced by lead and arsenic in male rats. Journal of Chemistry. 2021; 2021: 1–12. https://doi.org/10.1155/2021/9589345.

[81] Jurado-Campos A, Soria-Meneses PJ, Arenas-Moreira M, Alonso-Moreno C, Rodríguez-Robledo V, Soler AJ, et al. Minimizing sperm oxidative stress using nanotechnology for breeding programs in rams. Journal of Animal Science and Biotechnology. 2023; 14: 106. https://doi.org/10.1186/s40104-023-00907-3.

[82] Jurado-Campos A, Soria-Meneses PJ, Sánchez-Rubio F, Niza E, Bravo I, Alonso-Moreno C, et al. Vitamin E Delivery Systems Increase Resistance to Oxidative Stress in Red Deer Sperm Cells: Hydrogel and Nanoemulsion Carriers. Antioxidants. 2021; 10: 1780. https://doi.org/10.3390/antiox10111780.

[83] Sánchez-Rubio F, Soria-Meneses PJ, Jurado-Campos A, Bartolomé-García J, Gómez-Rubio V, Soler AJ, et al. Nanotechnology in reproduction: Vitamin E nanoemulsions for reducing oxidative stress in sperm cells. Free Radical Biology & Medicine. 2020; 160: 47–56. https://doi.org/10.1016/j.freeradbiomed.2020.07.024.

[84] Alizadeh F, Javadi M, Karami AA, Gholaminejad F, Kavianpour M, Haghighian HK. Curcumin nanomicelle improves semen parameters, oxidative stress, inflammatory biomarkers, and reproductive hormones in infertile men: A randomized clinical trial. Phytotherapy Research. 2018; 32: 514–521. https://doi.org/10.1002/ptr.5998.

[85] Ono T, Takada S, Kinugawa S, Tsutsui H. Curcumin ameliorates skeletal muscle atrophy in type 1 diabetic mice by inhibiting protein ubiquitination. Experimental Physiology. 2015; 100: 1052–1063. https://doi.org/10.1113/EP085049.

[86] Khushboo M, Murthy MK, Devi MS, Sanjeev S, Ibrahim KS, Kumar NS, et al. Testicular toxicity and sperm quality following copper exposure in Wistar albino rats: ameliorative potentials of L-carnitine. Environmental Science and Pollution Research International. 2018; 25: 1837–1862. https://doi.org/10.1007/s11356-017-0624-8.

[87] Li Y, Chen H, Liao J, Chen K, Javed MT, Qiao N, et al. Long-term copper exposure promotes apoptosis and autophagy by inducing oxidative stress in pig testis. Environmental Science and Pollution Research International. 2021; 28: 55140–55153. https://doi.org/10.1007/s11356-021-14853-y.

[88] Yang SH, He JB, Yu LH, Li L, Long M, Liu MD, et al. Protective role of curcumin in cadmium-induced testicular injury in mice by attenuating oxidative stress via Nrf2/ARE pathway. Environmental Science and Pollution Research International. 2019; 26: 34575–34583. https://doi.org/10.1007/s11356-019-06587-9.

[89] Abedin SN, Baruah A, Baruah KK, Bora A, Dutta DJ, Kadirvel G, et al. Zinc oxide and selenium nanoparticles can improve semen quality and heat shock protein expression in cryopreserved goat (Capra hircus) spermatozoa. Journal of Trace Elements in Medicine and Biology. 2023; 80: 127296. https://doi.org/10.1016/j.jtemb.2023.127296.

[90] Omu AE, Al-Azemi MK, Al-Maghrebi M, Mathew CT, Omu FE, Kehinde EO, et al. Molecular basis for the effects of zinc deficiency on spermatogenesis: An experimental study in the Sprague-dawley rat model. Indian Journal of Urology. 2015; 31: 57–64. https://doi.org/10.4103/0970-1591.139570.

[91] Wang H, Zhang J, Yu H. Elemental selenium at nano size possesses lower toxicity without compromising the fundamental effect on selenoenzymes: comparison with selenomethionine in mice. Free Radical Biology & Medicine. 2007; 42: 1524–1533. https://doi.org/10.1016/j.freeradbiomed.2007.02.013.

[92] Akiyama M. In vivo scavenging effect of ethylcysteine on reactive oxygen species in human semen. The Japanese Journal of Urology. 1999; 90: 421–428. https://doi.org/10.5980/jpnjurol1989.90.421.

[93] Paul DR, Talukdar D, Ahmed FA, Lalrintluanga K, Kalita G, Tolenkhomba TC, et al. Effect of selenium nanoparticles on the quality and fertility of short-term preserved boar semen. Frontiers in Veterinary Science. 2024; 10: 1333841. https://doi.org/10.3389/fvets.2023.1333841.

[94] Horky P, Urbankova L, Bano I, Kopec T, Nevrkla P, Pribilova M, et al. Selenium Nanoparticles as Potential Antioxidants to Improve Semen Quality in Boars. Animals. 2023; 13: 2460. https://doi.org/10.3390/ani13152460.

[95] Pardhiya S, Priyadarshini E, Rajamani P. In vitro antioxidant activity of synthesized BSA conjugated manganese dioxide nanoparticles. SN Applied Sciences. 2020; 2: 1–12.

[96] Zhang Y, Chen L, Sun R, Lv R, Du T, Li Y, et al. Multienzymatic Antioxidant Activity of Manganese-Based Nanoparticles for Protection against Oxidative Cell Damage. ACS Biomaterials Science & Engineering. 2022; 8: 638–648. https://doi.org/10.1021/acsbiomaterials.1c01286.

[97] Gautam R, Singh KV, Nirala J, Murmu NN, Meena R, Rajamani P. Oxidative stress-mediated alterations on sperm parameters in male Wistar rats exposed to 3G mobile phone radiation. Andrologia. 2019; 51: e13201. https://doi.org/10.1111/and.13201.

[98] Paskeh MDA, Babaei N, Hashemi M, Doosti A, Hushmandi K, Entezari M, et al. The protective impact of curcumin, vitamin D and E along with manganese oxide and Iron (III) oxide nanoparticles in rats with scrotal hyperthermia: Role of apoptotic genes, miRNA and circRNA. Journal of Trace Elements in Medicine and Biology. 2024; 81: 127320. https://doi.org/10.1016/j.jtemb.2023.127320.

[99] Das S, Dowding JM, Klump KE, McGinnis JF, Self W, Seal S. Cerium oxide nanoparticles: applications and prospects in nanomedicine. Nanomedicine. 2013; 8: 1483–1508. https://doi.org/10.2217/nnm.13.133.

[100] Celardo I, Pedersen JZ, Traversa E, Ghibelli L. Pharmacological potential of cerium oxide nanoparticles. Nanoscale. 2011; 3: 1411–1420. https://doi.org/10.1039/c0nr00875c.

[101] Filippi A, Liu F, Wilson J, Lelieveld S, Korschelt K, Wang T, et al. Antioxidant activity of cerium dioxide nanoparticles and nanorods in scavenging hydroxyl radicals. RSC advances. 2019; 9: 11077-11081. https://doi.org/10.1039/c9ra00642g.

[102] Shcherbakov A, Ivanov V, Zholobak N, Ivanova O, Krysanov EY, Baranchikov A, et al. Nanocrystalline ceria based materials—Perspectives for biomedical application. Biophysics. 2011; 56: 987–1004.

[103] Korsvik C, Patil S, Seal S, Self WT. Superoxide dismutase mimetic properties exhibited by vacancy engineered ceria nanoparticles. Chemical Communications. 2007; 1056–1058. https://doi.org/10.1039/b615134e.

[104] Heckert EG, Karakoti AS, Seal S, Self WT. The role of cerium redox state in the SOD mimetic activity of nanoceria. Biomaterials. 2008; 29: 2705–2709. https://doi.org/10.1016/j.biomaterials.2008.03.014.

[105] Pirmohamed T, Dowding JM, Singh S, Wasserman B, Heckert E, Karakoti AS, et al. Nanoceria exhibit redox state-dependent catalase mimetic activity. Chemical Communications. 2010; 46: 2736–2738. https://doi.org/10.1039/b922024k.

[106] Karakoti AS, Singh S, Kumar A, Malinska M, Kuchibhatla SVNT, Wozniak K, et al. PEGylated nanoceria as radical scavenger with tunable redox chemistry. Journal of the American Chemical Society. 2009; 131: 14144–14145. https://doi.org/10.1021/ja9051087.

[107] Nosenko ND, Zholobak NM, Poliakova LI, Sinitsyn PV, Lymarieva AA, Shcherbakov OV, et al. Morphofunctional state of reproductive system of ageing male rats in case of using nanocerium. Fiziolohichnyi Zhurnal. 2014; 60: 11–17.

[108] Zhai Q, Narbad A, Chen W. Dietary strategies for the treatment of cadmium and lead toxicity. Nutrients. 2015; 7: 552–571. https://doi.org/10.3390/nu7010552.

[109] Nasiri AH, Towhidi A, Zeinoaldini S. Combined effect of DHA and α-tocopherol supplementation during bull semen cryopreservation on sperm characteristics and fatty acid composition. Andrologia. 2012; 44: 550–555. https://doi.org/10.1111/j.1439-0272.2011.01225.x.

[110] Yuan C, Wang H, Li X, Liu H, Zhao J, Lu W, et al. Combined Effect of Flaxseed Oil and Vitamin E Supplementation During Bull Semen Cryopreservation on Sperm Characteristics. Biopreservation and Biobanking. 2022; 20: 520–528. https://doi.org/10.1089/bio.2021.0059.

[111] Peña FJ, Johannisson A, Wallgren M, Rodriguez Martinez H. Antioxidant supplementation in vitro improves boar sperm motility and mitochondrial membrane potential after cryopreservation of different fractions of the ejaculate. Animal Reproduction Science. 2003; 78: 85–98. https://doi.org/10.1016/s0378-4320(03)00049-6.

[112] Taylor K, Roberts P, Sanders K, Burton P. Effect of antioxidant supplementation of cryopreservation medium on post-thaw integrity of human spermatozoa. Reproductive Biomedicine Online. 2009; 18: 184–189. https://doi.org/10.1016/s1472-6483(10)60254-4.

[113] Harrison D, Griendling KK, Landmesser U, Hornig B, Drexler H. Role of oxidative stress in atherosclerosis. The American Journal of Cardiology. 2003; 91: 7A–11A. https://doi.org/10.1016/s0002-9149(02)03144-2.

[114] La Vignera S, Calogero AE, Condorelli R, Lanzafame F, Giammusso B, Vicari E. Andrological characterization of the patient with diabetes mellitus. Minerva Endocrinologica. 2009; 34: 1–9.

[115] La Vignera S, Condorelli R, Vicari E, D’Agata R, Calogero AE. Diabetes mellitus and sperm parameters. Journal of Andrology. 2012; 33: 145–153. https://doi.org/10.2164/jandrol.111.013193.

[116] Zhang W, Tong L, Jin B, Sun D. Diabetic testicular dysfunction and spermatogenesis impairment: mechanisms and therapeutic prospects. Frontiers in Endocrinology. 2025; 16: 1653975. https://doi.org/10.3389/fendo.2025.1653975.

[117] Afifi M, Almaghrabi OA, Kadasa NM. Ameliorative Effect of Zinc Oxide Nanoparticles on Antioxidants and Sperm Characteristics in Streptozotocin-Induced Diabetic Rat Testes. BioMed Research International. 2015; 2015: 153573. https://doi.org/10.1155/2015/153573.

[118] El-Behery EI, El-Naseery NI, El-Ghazali HM, Elewa YHA, Mahdy EAA, El-Hady E, et al. The efficacy of chronic zinc oxide nanoparticles using on testicular damage in the streptozotocin-induced diabetic rat model. Acta Histochemica. 2019; 121: 84–93. https://doi.org/10.1016/j.acthis.2018.10.010.

[119] Howell SJ, Shalet SM. Testicular function following chemotherapy. Human Reproduction Update. 2001; 7: 363–369. https://doi.org/10.1093/humupd/7.4.363.

[120] Aliakbari F, Taghizabet N, Azizi F, Rezaei-Tazangi F, Samadee Gelehkolaee K, Kharazinejad E. A review of methods for preserving male fertility. Zygote. 2022; 30: 289–297. https://doi.org/10.1017/S0967199421000071.

[121] Elshamy AA, Kotram LE, Barakat OS, Mahmoud SM. The effects of green synthesized anionic cupric oxide nanoparticles on Zaraibi goat spermatozoa during cryopreservation with and without removal of seminal plasma. Animal Biotechnology. 2023; 34: 2582–2595. https://doi.org/10.1080/10495398.2022.2106992.

[122] Khalil WA, El-Harairy MA, Zeidan AEB, Hassan MAE, Mohey-Elsaeed O. Evaluation of bull spermatozoa during and after cryopreservation: Structural and ultrastructural insights. International Journal of Veterinary Science and Medicine. 2017; 6: S49–S56. https://doi.org/10.1016/j.ijvsm.2017.11.001.

[123] Aitken RJ, Clarkson JS, Fishel S. Generation of reactive oxygen species, lipid peroxidation, and human sperm function. Biology of Reproduction. 1989; 41: 183–197. https://doi.org/10.1095/biolreprod41.1.183.

[124] Safa S, Moghaddam G, Jozani RJ, Daghigh Kia H, Janmohammadi H. Effect of vitamin E and selenium nanoparticles on post-thaw variables and oxidative status of rooster semen. Animal Reproduction Science. 2016; 174: 100–106. https://doi.org/10.1016/j.anireprosci.2016.09.011.

[125] Khalil WA, El-Harairy MA, Zeidan AEB, Hassan MAE. Impact of selenium nano-particles in semen extender on bull sperm quality after cryopreservation. Theriogenology. 2019; 126: 121–127. https://doi.org/10.1016/j.theriogenology.2018.12.017.

[126] Khalique MA, Andrabi SMH, Majeed KA, Yousaf MS, Ahmad N, Tahir SK, et al. Cerium oxide nanoparticles improve the post-thaw quality and in-vivo fertility of Beetal buck spermatozoa. Theriogenology. 2024; 214: 166–172. https://doi.org/10.1016/j.theriogenology.2023.10.022.

[127] Bisla A, Rautela R, Yadav V, Singh P, Kumar A, Ghosh S, et al. Nano-purification of raw semen minimises oxidative stress with improvement in post-thaw quality of buffalo spermatozoa. Andrologia. 2020; 52: e13709. https://doi.org/10.1111/and.13709.

[128] Isaac AV, Kumari S, Nair R, Urs DR, Salian SR, Kalthur G, et al. Supplementing zinc oxide nanoparticles to cryopreservation medium minimizes the freeze-thaw-induced damage to spermatozoa. Biochemical and Biophysical Research Communications. 2017; 494: 656–662. https://doi.org/10.1016/j.bbrc.2017.10.112.

[129] Shahin MA, Khalil WA, Saadeldin IM, Swelum AA, El-Harairy MA. Effects of vitamin C, vitamin E, selenium, zinc, or their nanoparticles on camel epididymal spermatozoa stored at 4 °C. Tropical Animal Health and Production. 2021; 53: 86. https://doi.org/10.1007/s11250-020-02521-1.

[130] Falchi L, Galleri G, Dore GM, Zedda MT, Pau S, Bogliolo L, et al. Effect of exposure to CeO₂ nanoparticles on ram spermatozoa during storage at 4 °C for 96 hours. Reproductive Biology and Endocrinology. 2018; 16: 19. https://doi.org/10.1186/s12958-018-0339-9.

[131] Pinho AR, Rebelo S, Pereira ML. The Impact of Zinc Oxide Nanoparticles on Male (In)Fertility. Materials. 2020; 13: 849. https://doi.org/10.3390/ma13040849.

[132] Jurado-Campos A, Soria-Meneses PJ, Arenas-Moreira M, Alonso-Moreno C, Bravo I, Rodríguez-Robledo V, et al. Vitamin E Lipid-Based Nanodevices as a Tool for Ovine Sperm Protection against Oxidative Stress: Impact on Sperm Motility. Antioxidants. 2022; 11: 1988. https://doi.org/10.3390/antiox11101988.

[133] Badkoobeh P, Parivar K, Kalantar SM, Hosseini SD, Salabat A. Effect of nano-zinc oxide on doxorubicin- induced oxidative stress and sperm disorders in adult male Wistar rats. Iranian Journal of Reproductive Medicine. 2013; 11: 355–364.

[134] Anan HH, Zidan RA, Abd El-Baset SA, Ali MM. Ameliorative effect of zinc oxide nanoparticles on cyclophosphamide induced testicular injury in adult rat. Tissue & Cell. 2018; 54: 80–93. https://doi.org/10.1016/j.tice.2018.08.006.

[135] Mohammadi T, Hoveizi E, Khajehpour L, Jelodar Z. Protective effects of zinc oxide nanoparticles on testis histological structure in cyclophosphamide treated adult mice. Journal of Mazandaran University of Medical Sciences. 2017; 26: 19–27.

[136] Rezvanfar MA, Rezvanfar MA, Shahverdi AR, Ahmadi A, Baeeri M, Mohammadirad A, et al. Protection of cisplatin-induced spermatotoxicity, DNA damage and chromatin abnormality by selenium nano-particles. Toxicology and Applied Pharmacology. 2013; 266: 356–365. https://doi.org/10.1016/j.taap.2012.11.025.

[137] Mobaraki F, Momeni M, Barghbani M, Far BF, Hosseinian S, Hosseini SM. Extract-mediated biosynthesis and characterization of gold nanoparticles: Exploring their protective effect against cyclophosphamide-induced oxidative stress in rat testis. Journal of Drug Delivery Science and Technology. 2022; 71: 103306. https://doi.org/10.1016/j.jddst.2022.103306.

[138] Ma J, Dong S, Lu H, Chen Z, Yu H, Sun X, et al. The hydrogen storage nanomaterial MgH₂ improves irradiation-induced male fertility impairment by suppressing oxidative stress. Biomaterials Research. 2022; 26: 20. https://doi.org/10.1186/s40824-022-00266-6.

[139] Fornaguera C, García-Celma MJ. Personalized Nanomedicine: A Revolution at the Nanoscale. Journal of Personalized Medicine. 2017; 7: 12. https://doi.org/10.3390/jpm7040012.

[140] Garrido N, Hervás I. Personalized Medicine in Infertile Men. The Urologic Clinics of North America. 2020; 47: 245–255. https://doi.org/10.1016/j.ucl.2019.12.011.

[141] Vanderhout SM, Rastegar Panah M, Garcia-Bailo B, Grace-Farfaglia P, Samsel K, Dockray J, et al. Nutrition, genetic variation and male fertility. Translational Andrology and Urology. 2021; 10: 1410–1431. https://doi.org/10.21037/tau-20-592.

[142] Zhang XQ, Xu X, Bertrand N, Pridgen E, Swami A, Farokhzad OC. Interactions of nanomaterials and biological systems: Implications to personalized nanomedicine. Advanced Drug Delivery Reviews. 2012; 64: 1363–1384. https://doi.org/10.1016/j.addr.2012.08.005.