N -acetylcysteine and zinc sulphate abate di-2-ethylhexyl phthalate-mediated reproductive dysfunction in rats: Focus on oxidative and sex hormone receptors mechanisms

Abstract

Objective: To investigate the potential of N-acetylcysteine (NAC) and zinc sulphate (ZnSO₄) in mitigating reproductive dysfunction caused by di-2-ethylhexyl phthalate (DEHP) in rats and to understand the underlying mechanisms, specifically oxidative stress and sex hormone receptor activity.

Methods: Thirty-five male Wistar rats were randomly divided into five equal groups (n=7 per group). Group 1 was administered 0.5 mL of distilled water and served as the control group. Group 2 was given only DEHP (750 mg/kg/day), while group 3, 4 and 5 were given DEHP (750 mg/kg/day) plus NAC (100 mg/kg/day), DEHP (750 mg/kg/day) plus ZnSO₄ (0.5 mg/kg/day), and DEHP (750 mg/kg/day) plus NAC (100 mg/kg/day) as well as ZnSO₄ (0.5 mg/kg/day), respectively. All treatments lasted for 21 days. Samples were obtained after the rats were sacrificed, and hormones levels in the serum and markers of oxidative stress in the testicles were analyzed using the enzyme-linked immunosorbent assay. The amount of androgen receptors in the testicles was determined by immunohistochemistry, and the susceptibility of testosterone and DEHP to bind to androgen receptor and 5α-reductase was determined by molecular docking studies.

Results: DEHP decreased reproductive hormones, testicular antioxidant enzymes, increased malondialdehyde levels, and negatively impacted histology of the pituitary and testes. NAC or ZnSO₄ treatment showed a marked improvement in testicular antioxidant status and hormone levels, as well as a positive effect on the histology of the pituitary and testes. The combination of both treatments appeared to be more effective. The affinity of DEHP to bind to androgen receptors may lead to disruption of androgen receptor signaling, which can further result in dysfunction of hormones related to androgen. However, NAC is more likely to form stronger binding interactions with follicle stimulating hormone and luteinizing hormone receptors, as well as gonadotropin-releasing hormone receptors, when compared to DEHP.

Conclusions: The possibility that NAC and ZnSO₄ could downregulate DEHP-induced sex hormone changes is suggested by their potential to reduce toxicity.

Keywords

Di-2-ethylhexyl phthalate / Testosterone / Androgen receptor / 5α-reductase / Oestrogen / Luteinizing hormone

Conflict of interest statement

Authors declare that they have no conflict of interest

Acknowledgements

The authors are very grateful to the technical staff of the Department of Physiology and the animal house unit of the Delta State University, Abraka, Delta State for their technical input in the study.

Funding

The study was done with author’s financial contribution and did not receive any sponsorship from any agency.

Data availability statement

Data are available on request from the corresponding author.

Authors’ contributions

Eze Kingsley Nwangwa and Alexander Obidike Naiho conceived, designed and co-supervised the research; Motunrayo Lade-Ige and Victor Omo-Idonije conducted the experiments; Victor Oghenekparobo Emojevwe, Kayode Ezekiel Adewole, Peggy Ejiro Ohwin, Adeniran Oluwadamilare Akinola and Benneth Ben-Azu wrote the manuscript and contributed reagents; Mega Obukohwo Oyovwi and Victor Oghenekparobo Emojevwe conducted experiments while Kayode Ezekiel Adewole did the insilico docking with Oghenekparobo Emojevwe. Mega Obukohwo Oyovwi collected samples and analyzed the data and helped Victor Oghenekparobo Emojevwe with literature search. All authors read and approved the manuscript.

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