Background: Young ovarian cancer (OC) patients often experience a synergistic interplay among tumor progression, estrogen deficiency, and depression, which severely compromises prognosis and quality of life. However, a preclinical model that faithfully recapitulates this triad remains lacking. This study aimed to develop and validate a novel mouse model to investigate the interrelationship between ovarian cancer, hypoestrogenic states, and depression.

Methods: An ovarian cancer–related depression (OCRD) model was established by integrating previously validated components of tumor-depression paradigms, including ID-8 ovarian cancer modeling and chronic restraint stress-induced depressive-like behavior. Orthotopic (intraperitoneal) and heterotopic (subcutaneous) tumor models were combined with chronic stress. Estrogen status was manipulated by ovary retention or ovariectomy (OVX), performed either 1 day before tumor implantation to model preexisting estrogen deficiency or 7 days after engraftment to mimic treatment-induced abrupt hormonal loss. Model validity was assessed using behavioral assays (sucrose preference test, tail suspension test, and open field test), neuroendocrine profiling, and longitudinal evaluation of tumor progression.

Results: The model generated by intraperitoneal tumor engraftment, OVX, and chronic stress exhibited pronounced depressive-like behavior, accompanied by marked estrogen depletion and accelerated tumor progression. All mice survived throughout the experimental period, indicating high model stability and reproducibility. This integrated phenotype closely mirrors key clinical features observed in young OC patients undergoing abrupt estrogen deprivation.

Conclusions: The combination of intraperitoneal ovarian cancer modeling, ovariectomy, and chronic stress induction establishes a stable and clinically relevant preclinical model of hypoestrogenic ovarian cancer–related depression, suitable for translational research.

Background: The development of effective therapeutic strategies for late-stage estrogen receptor-positive breast cancer (ER+) is limited by the scarcity of biologically relevant models. More recently, immunotherapies emerged as promising candidates for breast cancer treatment, however, the absence of immunocompetent models of ER+ breast cancer metastasis continues to hinder the assessment of these theraputic interventions.

Methods: To address this, we utilized the 129S6/SvEv mouse strain and syngeneic SSM3 cells in the assessment and development of ER+ metastasis models. As part of this study, the mammary intraductal (MIND) primary tumor model was established in the same background. In addition, a novel luciferase system was evaluated for potential use in metastasis tracking.

Results: Luciferase-expressing SSM3 cells enabled longitudinal in vivo imaging to track tumor growth. Histological analysis confirmed metastatic spread and tumor origin. Antares2, a novel luciferase reporter, showed high in vitro sensitivity but reduced in vivo performance. The study showed that systemic delivery of SSM3 cells with oestradiol supplementation can support metastatic tumor establishment and that MIND injections led to reliable, invasive tumor growth.

Conclusions: These findings highlight the potential and limitations of the 129S6/SvEv model as a syngeneic, immunocompetent system for studying ER+ breast cancer metastasis. Reporter expression may affect immunogenicity or cell fitness. Further refinement of these models will enable investigation of immune-modulatory therapies in ER+ metastatic breast cancer.

Background: Currently, there is a lack of an adequate rodent model for investigating surgical techniques and comprehensive treatment options for patients with colorectal cancer (CRC). This study presents a mouse model that involves the orthotopic implantation of colon cancer, followed by a limited colectomy, with the aim of addressing this issue.

Methods: To establish an early colon tumor model, luciferase-tagged CT-26 cells were implanted into the ascending colon wall of BALB/c mice. After a 1-week observation period, a limited colectomy procedure was performed. The progression of cancer and the impact of resection were monitored using bioluminescence imaging. Additionally, both short-term and long-term effects of surgical intervention were assessed.

Results: The study demonstrated a 100% success rate (40/40) in establishing the BALB/c mouse model of early colon cancer. The technical success rate of limited colectomy was also 100%, with no instances of early mortality or morbidity. After the limited colectomy procedure, none of the animals exhibited any primary tumors, bloody ascites, recurrence or local invasion, intestinal obstruction, lymph node metastasis, peritoneal seeding, or anastomotic leakage. Furthermore, there were no reported deaths during the postresection observation period in animals treated with limited colectomy.

Conclusion: In summary, our research group has successfully described a novel and reproducible surgical resection model for colon cancer in mice, which reflects the clinical scenario.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare, yet life-threatening disorder characterized by persistent pulmonary vascular obstruction and elevated pulmonary artery pressure, with progressive remodeling and subsequent right heart failure. Despite substantial progress in elucidating the pathophysiology of CTEPH, the molecular mechanisms driving disease initiation and progression remain incompletely defined. Bridging these knowledge gaps and enabling the development of CTEPH-specific therapeutic strategies depend on experimental models that faithfully recapitulate the key pathological features observed in patients. A wide range of small- and large-animal models has therefore been established to mimic CTEPH development, each offering specific strengths and inherent limitations. Small animal models are relatively inexpensive, readily amenable to genetic manipulation, and well suited for high-throughput mechanistic investigations. However, their capacity to reproduce the complex pulmonary vascular architecture and hemodynamic characteristics of human disease is limited. By comparison, large-animal models more closely approximate human pulmonary anatomy and cardiovascular physiology, making them particularly valuable for detailed hemodynamic measurements and advanced imaging studies. Their broader application, however, is constrained by high financial costs, ethical considerations, and the need for specialized surgical and monitoring techniques. In this review, we provide an overview of currently available animal models of CTEPH, with emphasis on their methodological features, their ability to reproduce clinically relevant disease characteristics, and their potential utility in preclinical and translational research.

The horse is a distinctive translational model for bridging mechanistic discovery and clinically relevant investigation because of its physiological complexity, long lifespan, athletic phenotype, and broad spectrum of naturally occurring conditions that parallel aspects of human health and disease. Its utility extends from musculoskeletal and joint research to immunology, metabolic disorders, and exercise physiology, particularly where naturally developed disease, clinically applicable imaging, and longitudinal sampling are required. Additionally, it offers opportunities to examine both chronic and acute pathological processes in a setting that closely approximates clinical reality. Advances in molecular profiling, imaging technologies, and biomarker discovery have expanded the scope of equine-based studies, enabled refined mechanistic insights, and facilitated translational strategies. The integration of equine research into comparative medicine frameworks holds promise for accelerating therapeutic innovation within comparative and One-Health, improving health outcomes across species.

Over the past several decades, humanized mouse models have undergone significant refinement and become essential tools in biomedical research. Advances in genetic engineering, particularly the targeted knock-in of human cytokines, have enabled robust development and function of human immune cells in these models. Recent breakthroughs—including the directed differentiation of human pluripotent stem cells into thymic epithelial cells and the efficient expansion of hematopoietic stem cells—have alleviated the constraint of scarce human tissue sources. Furthermore, the reconstruction of lymph node structures and successful engraftment of solid organ tissues have significantly improved the efficiency and physiological relevance of human immune system reconstitution. These models now provide a unique platform for in vivo studies in cancer immunotherapy, infectious diseases, regenerative medicine, and autoimmune disorders under near-physiological conditions. Beyond rodents, substantial progress in humanized large animals, such as pigs, offers promising avenues for large-scale immune system reconstruction and mass production of immunotherapeutic cells. This review presents a comprehensive overview of the development, optimization, and expanding applications of humanized animal models, highlighting their transformative role in advancing translational medicine.

Background: This study aimed to investigate the potential causal relationship between genetically predicted human blood cell (HBC) reactivity and disorders of bone continuity, density, and structure.

Methods: We analyzed summary-level GWAS data for 91 HBC traits and two bone-related outcomes from publicly available sources, employing the inverse-variance weighted (IVW) method as the principal Mendelian randomization (MR) technique. The sensitivity analyses comprised MR-Egger regression and MR-PRESSO.

Results: MR analysis identified suggestive associations between red blood cell (RBC) perturbation response (Pam3CSK4), neutrophil perturbation response (side fluorescence coefficient of variation of neutrophil 4), Neutrophil perturbation response (colchicine), Monocyte perturbation response (TMAO perturbation) and bone continuity. The MR results are: [β: −0.13, odds ratio (OR): 0.88; 95% confidence interval (CI): 0.77, 0.99; p = 0.040], [β: 0.11, OR: 1.12, 95% CI: 1.02, 1.23; p = 0.016], [β: −0.11, OR: 0.90, 95% CI: 0.81, 0.99; p = 0.029] and [β: −0.04, OR: 0.96, 95% CI: 0.92, 0.99; p = 0.023]. In addition, Neutrophil perturbation response (forward scatter median of neutrophil 1), Unknown cell population perturbation response (nigericin) and other disorders of bone density and structure are also potential causal factors, with MR Result [β: 0.21, OR: 1.24, 95%CI: 1.01, 1.51; p = 0.034], [β: 0.03, OR: 1.03, 95% CI: 1.00, 1.06; p = 0.042]. Reverse Mendelian randomization sensitivity analysis showed a potential bidirectional association between specific HBC features and bone-related outcomes.

Conclusions: This exploratory study offer valuable preliminary insights into the blood cell functional reactivity and bone health. The findings, while requiring independent validation, highlight plausible biological pathways for further elucidation.

Background: This study aimed to investigate the mechanisms by which Citrus aurantium honey modulates gastrointestinal motility, inflammation, and barrier function using network pharmacology and Drosophila melanogaster models.

Methods: Ultra-high-performance liquid chromatography coupled with Q Exactive high-field mass spectrometry (UHPLC-Q Exactive HF-MS) characterized the chemical profile. Network pharmacology predicted targets and enriched pathways, and molecular docking validated core component–target binding. In lipopolysaccharide (LPS)-induced Drosophila intestinal injury models, functional assays (fecal excretion, intestinal transit, barrier integrity) and mechanistic analyses (reactive oxygen species [ROS] levels, TORC1 pathway–related protein/gene expression) were performed.

Results: Network pharmacology revealed 17 key targets enriched in calcium signaling, cAMP/cGMP-PKG, and neuroactive ligand–receptor pathways. In Drosophila, honey dose-dependently (0.25% < 0.5% < 1%) enhanced intestinal motility (increased volume of stool and shorter transit time) and reduced inflammation (reduced ROS levels and improved barrier integrity, p < 0.01). Mechanistically, honey inhibited TORC1 overactivation by reducing 4E-BP phosphorylation and regulating Thor/Nprl2 expression.

Conclusions: C. aurantium honey exerts gastrointestinal effects via a “multi-component, multi-target” mechanism. It modulates smooth muscle contraction through calcium/cAMP/cGMP pathways and alleviates inflammation by suppressing TORC1 signaling, highlighting its potential as a dietary intervention for dysmotility and inflammation.

Background: Gut barrier integrity prevents microbial translocation and systemic infection. Chronic alcohol disrupts this barrier, but its role in infection susceptibility among immune-compromised hosts remains unclear. We investigated how chronic alcohol promotes gut barrier dysfunction, endotoxemia, and dysbiosis, predisposing to bacterial translocation and sepsis.

Methods: Twenty-four-week-old female FcγRIIb^−/− and wild-type mice received oral gavage of 35% ethanol (4.2 g/kg/day) or water for 10 weeks. Gut barrier integrity was assessed by serum endotoxin, FITC-dextran permeability, ileal claudin-1, and intestinal IgG/neutrophil infiltration. Systemic inflammation was evaluated by serum TNF-α, IL-1β, and IL-6; gut microbiota by 16S rRNA sequencing. Bone marrow–derived macrophages and hepatocytes from both genotypes were stimulated with LPS or ethanol to assess inflammatory responses, mitochondrial damage, and cGAS-STING activation.

Results: Chronic alcohol induced gut barrier dysfunction in both groups, with more severe effects in FcγRIIb^−/− mice, which showed marked increases in serum endotoxin and FITC-dextran permeability, reduced claudin-1, and enhanced intestinal IgG deposition with neutrophil accumulation. Serum TNF-α, IL-1β, and IL-6 were significantly elevated, reflecting a sepsis-like profile. Alcohol induced dysbiosis with an increased Firmicutes-to-Bacteroidota ratio, elevated Lachnospiraceae, and reduced Alistipes, Bacteroides, and Odoribacter. In vitro, LPS elicited stronger inflammation than ethanol in both cell types, with FcγRIIb^−/− cells producing greater cytokine levels. Both stimuli caused comparable mitochondrial damage and cGAS-STING activation.

Conclusions: Alcohol-induced gut barrier dysfunction, endotoxemia, and dysbiosis predispose to bacterial translocation and early sepsis, particularly in hosts with impaired inhibitory Fcγ receptor signaling, supporting gut barrier preservation as a strategy for preventing alcohol-associated infections and sepsis.

Background: Human cytomegalovirus (HCMV) infection is related to the acceleration of transplant vascular sclerosis, atherosclerosis, and coronary restenosis. A shared theme of these vascular illnesses is pathologic angiogenesis. Nevertheless, how HCMV infection causes angiogenesis is not fully understood. Human serum contains HCMV-encoded miRNAs, and it is unclear whether these virus-derived miRNAs can regulate angiogenesis. This research looks into HCMV-encoded miRNA's role in angiogenesis of endothelial cells.

Methods: Endothelial cell proliferation was examined by CCK8 assay, and cell migration capability was established using a Transwell Boyden Chamber. Western blotting alongside luciferase reporter assay verified the direct regulation of FOXO3 by HCMV-encoded miRNAs, including hcmv-miR-UL36-3p. hcmv-miR-UL36-3p's pro-angiogenic action was examined by angiogenesis assays (in vivo) and capillary tube formation (in vitro), which were performed by giving C57BL/6J mice subcutaneous Matrigel injections containing bFGF along with simultaneous injections of either hcmv-miR-UL36-3p or ncRNA once every 4 days. After 8 days, Matrigel plugs were examined.

Results: hcmv-miR-UL36-3p was upregulated in patients with atherosclerosis. Overexpression of hcmv-miR-UL36-3p enhanced capillary tube development, motility, and proliferation in endothelial cells. hcmv-miR-UL36-3p promoted endothelial cell tube formation through directly binding to and downregulating FOXO3. Experiments in mice further confirmed that hcmv-miR-UL36-3p promoted angiogenesis in vivo.

Conclusions: The HCMV-encoded miR-UL36-3p can trigger angiogenesis in endothelial cells by targeting FOXO3. Our work provides a conceivable mechanism of how HCMV-encoded miRNAs contribute to vascular illness.

Background: Scalp electroacupuncture (SA) has been clinically used as a novel treatment for ischemic stroke and depression. This study aimed to investigate whether stimulation of SA of the Baihui (GV20) and Yintang (EX-HN3) acupoints, which regulate the trigeminal nerve (TN), can alleviate depression and anxiety caused by post-traumatic stress disorder (PTSD) and to identify its therapeutic mechanism.

Methods: After stimulation of SA, vasodilation and leakage within the TN area and c-Fos expression in the TN pathway of the brain were analyzed. Also, the anti-inflammatory, antidepressant, and anxiolytic effects of SA were investigated in a mouse model of PTSD induced by single prolonged stress.

Results: SA activated the TN pathway, inducing vasodilation along the TN pathway, and increased c-Fos expression in the brain, including the spinal trigeminal nucleus, locus coeruleus (LC), amygdala, and entorhinal cortex. SA significantly alleviated depression- and anxiety-related behaviors, decreased pro-inflammatory cytokines, and increased the expression of neurotrophic factors in the hippocampus. Also, SA decreased the expression of P2X7 receptors in the microglia and norepinephrine transporter in the LC and hippocampus.

Conclusions: These results demonstrated that SA exhibited anti-inflammatory, antidepressant, and anxiolytic effects through the P2X7 receptor pathway and the LC-norepinephrine system.

Background: Aspiration pneumonia (AP) is a prevalent and life-threatening pulmonary disease resulting from repeated aspiration of exogenous materials such as food or gastric contents. However, most existing animal models simulate only acute injury and fail to reproduce the chronic pathological features observed in patients. This study aimed to establish a stable and clinically relevant chronic AP mouse model.

Methods: First, four inhalation techniques including unilateral vagotomy (UV), intranasal inoculation (IN), intratracheal instillation (IT), and oropharyngeal aspiration (OA) were evaluated for model establishment in mice. The optimal method OA was applied to administer normal saline (NS), food suspension (FS), or gastric contents (GC) once weekly. Disease progression was evaluated at 2, 4, and 8 weeks. Lung injury was evaluated by tracer distribution, histopathology, cytokine profiling, transcriptomic analysis, and micro-computed tomography (micro-CT).

Results: OA achieved stable pulmonary delivery. Both FS and GC induced lung injury. However, 8-week FS exposure resulted in more severe and persistent damage, characterized by increased alveolar–capillary barrier permeability and elevated cytokine and chemokine levels. Histology showed FS-specific obstructive bronchiolitis with retained food particles, closely mimicking human aspiration pneumonia. Micro-CT revealed gravity-dependent pulmonary consolidation, most evident in the FS group. Transcriptomic analysis indicated activation of neutrophil extracellular traps (NETs) formation during chronic AP progression.

Conclusions: This OA-based FS model reproduced the key pathological and imaging features of human chronic AP and implicated NETs in the disease progression. It provides a robust platform for mechanistic investigation and therapeutic development.

Background: Mouse models are commonly used to study asthma. Oscillometry, a technique using small-amplitude maneuvers, is often used to probe physiological lung alterations in mice. However, the changes in oscillometric readouts in mouse models of asthma are typically subtle, implying the need for using large sample sizes. Herein, lung maneuvers of different amplitudes were used to compare their sensitivity in detecting physiological alterations in mouse models of asthma.

Methods: Female BALB/c mice were exposed to saline or house dust mite (HDM) intranasally to induce experimental asthma. They were exposed either thrice per week for 5 weeks (long protocol) or for 10 consecutive days (short protocol). The presence of physiological alterations was tested using lung maneuvers of small amplitudes (oscillometry), intermediate amplitudes (the partial pressure–volume maneuver), and large amplitudes (full-range pressure–volume maneuvers) to quantify equivalent readouts, such as compliance, within different ranges of lung volumes.

Results: The differences between saline- and HDM-exposed mice increase with the maneuver amplitude. In the long protocol, for example, the decreased compliance caused by HDM was on average 3.2% (p = 0.39), 6.6% (p = 0.060), and 37.7% (p < 0.0001) when tested with maneuvers of small, intermediate, and large amplitudes, respectively. In the short protocol, these values were 3.1% (p = 0.35), 5.5% (p = 0.16), and 35.3% (p < 0.0001), respectively.

Conclusion: Lung maneuvers of large amplitudes can detect physiological alterations with a greater sensitivity in mouse models of asthma. These results are particularly useful for scientists using mouse models to test countermeasures, such as drugs, in asthma.

Background: Atherosclerosis begins with dyslipidemia, vascular inflammation, and endothelial dysfunction. Rodent models that capture these early events are needed for mechanistic and interventional studies. This study evaluated whether a cholesterol-rich, high-fat diet (HFD) supplemented with vitamin D and propylthiouracil (PTU) promotes a pro-atherogenic phenotype in rats, as evidenced by dyslipidemia, inflammation, markers of endothelial dysfunction, and early vascular remodeling.

Methods: Male Sprague–Dawley rats (n = 18) received standard chow or a HFD containing 2% cholesterol, 3% lard, 0.5% cholate, vitamin D (200 000 IU/kg), and PTU (0.2% w/w) for 11 weeks. Terminal serum total cholesterol, high-density lipoprotein, low-density lipoprotein (LDL)/very low-density lipoprotein (VLDL), triglycerides, calcium, interleukin-6 (IL-6), C-reactive protein, serum amyloid A (SAA), circulating endothelial nitric oxide synthase (eNOS), and intracellular adhesion molecule-1 (ICAM-1) were measured. The aorta, the coronary arteries, and the liver were examined histologically.

Results: HFD-fed rats developed significant hypercholesterolemia with higher total cholesterol and LDL/VLDL (p < 0.0001) and lower triglycerides (p < 0.0001) versus controls. Serum calcium was higher (p < 0.0001) without vascular calcification. Aortae exhibited wall thickening, smooth-muscle disarray, mononuclear infiltrates, and focal foam cell-like changes; coronary arteries exhibited endothelial irregularities and perivascular infiltrates. Livers exhibited micro- and macrovesicular steatosis. IL-6 and SAA were higher (p < 0.05), and circulating eNOS was lower (p < 0.05); ICAM-1 did not differ significantly.

Conclusion: An 11-week vitamin D/PTU-supplemented HFD induces an LDL-dominant dyslipidemia with systemic inflammation and evidence consistent with endothelial dysfunction, alongside histological features of early vascular remodeling and hepatic steatosis. This nongenetic model may be useful for studying early atherogenic changes.

Current models of endometriosis (EMs) still have limitations in replicating the key pathological features of human EMs, particularly the cyclic bleeding associated with ectopic lesions. To address this gap, this study aimed to develop a proof-of-concept mouse model that incorporates repeated retrograde hemorrhagic exposure through the intraperitoneal injection of endometrial fragments, followed by repeated intraperitoneal injections of fresh whole blood. An EMs model was established in female C57BL/6J mice via intraperitoneal injection of endometrial fragments combined with saline or whole blood, respectively. The model was systematically evaluated using ectopic lesion burden, peritoneal adhesion scores, histopathological staining, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and quantitative reverse transcription polymerase chain reaction (RT-qPCR). Both models successfully recapitulated the fundamental pathological features of EMs. However, the intraperitoneal injection of whole blood (IPBI) protocol induced a markedly greater lesion burden, together with more pronounced histopathological and molecular alterations, and recapitulated repeated exposure to retrograde menstruation. In addition, the IPBI group exhibited more robust systemic biomarker responses, indicating enhanced clinical relevance. The present study successfully established a proof-of-concept EMs mouse model that introduces repeated retrograde hemorrhagic exposure to create a clinically relevant, blood-stimulated microenvironment. This model provides a reliable tool for investigating the pathogenesis of EMs and developing therapeutic strategies.

The global spread of mpox continues to pose a threat to public health, with immunocompromised patients being at greater risk for severe disease. This study aimed to establish a lethal severe infection model using NPG (NOD.Cg-Prkdc^scidIl2rg^tm1/Vst) mice, a strain with profound immunodeficiency, to simulate severe mpox in immunocompromised patients and investigate disease progression, viral replication kinetics, tissue tropism, and immune responses. In our study, mice were inoculated with three doses of mpox virus (high: 2 × 10⁷, medium: 2 × 10⁶, low: 2 × 10⁵ TCID₅₀ [50% tissue culture infective dose]) or phosphate-buffered saline as a negative control. Body weight, clinical signs, and survival were monitored. Viral loads in plasma and tissues, histopathological changes, and inflammatory responses were evaluated to systematically characterize the pathogenicity of mpox virus in severely immunodeficient mice. The results showed that NPG mice were highly susceptible to mpox virus, showing a clear dose-dependent response. The high-dose group exhibited 100% lethality, and the medium-dose group had a 50% survival rate, whereas the low-dose and control groups survived throughout the study. Plasma and tissue viral loads, as well as histopathological severity, followed a dose-dependent pattern. Viremia remained persistently high, and animals that died at different time points exhibited uniformly high viral loads across multiple tissues. By day 10 postinfection, markedly elevated levels of pro-inflammatory cytokines were detected in plasma, whereas anti-inflammatory cytokines remained largely uninduced. We found that the infection of severely immunodeficient mice with mpox virus results in dose-dependent lethality, persistent high viral loads, and a pronounced pro−/anti-inflammatory imbalance. These findings provide important insights into the pathogenesis of mpox in immunocompromised populations and develop a practical animal model for evaluating therapeutic interventions.

Use of animals in biomedical research is still considered essential by many in academia, industry and regulatory authorities. Therefore, it is important that legal, governance and welfare procedures are in place to ensure that only necessary procedures using animals are carried out and that this occurs within a framework with animal welfare at its core. Animal research in the United Kingdom is conducted under the Animals (Scientific Procedures) Act 1986 and animal research in the United Kingdom has long been seen as a flag bearer for high quality–high welfare research. An example of the leading role taken in supporting animal welfare in research was establishment of the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) to support reducing the scale and impact of animal research. Here, we provide an overview of governance and licensing procedures of animal research in the United Kingdom, coupled with explanations of how excellent welfare underpins high quality research, and examine the development of new approach methodologies.