Search Results (1,142)

The molecular mechanisms underlying testicular development in the yak remain poorly understood. In this study, RNA sequencing was performed on testicular tissues from Tianzhu white yaks at three postnatal developmental stages: 0.5 (prepubertal), 2.5 (pubertal), and 4.5 (adult) years, with six animals in each group. Differential expression analysis was integrated with weighted gene co-expression network analysis (WGCNA) to characterize transcriptomic changes associated with testicular maturation. A total of 9646 differentially expressed genes (DEGs) were identified between the 0.5- and 2.5-year groups, whereas only 126 DEGs were detected between the 2.5- and 4.5-year groups, indicating that the transition to puberty represents the most dynamic phase of transcriptional reprogramming during testicular development. Functional enrichment analysis revealed that focal adhesion and extracellular matrix–receptor interaction were the most significantly enriched Kyoto Encyclopedia of Genes and Genomes pathways, suggesting a potential role for extracellular matrix (ECM) remodeling in the establishment of the blood–testis barrier and testicular maturation. WGCNA identified seven age-associated co-expression modules. The turquoise module showed the strongest positive correlation with developmental stage and was significantly enriched for genes involved in spermatid differentiation and maturation, including SPATA6, SPMIP11, TNP1, and ODF1. Collectively, these findings provide a comprehensive transcriptomic characterization of yak testicular development. Full article

Spermatogenesis in Drosophila melanogaster is a classical model for studying cell polarity establishment, organelle remodeling, and extreme cellular morphogenesis. Spermatid elongation involves a series of highly coordinated dynamic events, including nuclear polarization, axonemal extension, mitochondrial remodeling, and individualization-mediated cytoplasmic clearance. Current studies have largely focused on individual structures, molecules, or pathways, resulting in a fragmented understanding of this process and a lack of an integrated framework that links mitochondrial function, cytoskeletal dynamics, and temporal translational regulation. Based on existing evidence, this review organizes current findings into three regulatory layers involving mitochondrial remodeling, cytoskeletal dynamics, and post-transcriptional translational control. Mitochondrial remodeling provides structural and metabolic support for sperm-tail formation, cytoskeletal processes execute axoneme organization and individualization, and post-transcriptional regulation controls the timing of protein production. Experimental evidence is strongest for mechanisms operating within each layer, whereas direct molecular coupling among the three layers remains incompletely established. We therefore present this model as a working framework rather than an established causal pathway. This framework helps organize current knowledge of extreme cellular differentiation and provides a basis for comparative studies of spermatogenesis and selected mechanisms associated with human male infertility. Full article

Testicular germ cell tumors (TGCTs) are the most common solid malignancy in young men and are highly curable, making reproductive and endocrine survivorship central concerns. Gonadal dysfunction is often attributed to orchiectomy and gonadotoxic therapy, yet semen and hormonal abnormalities may already be present at diagnosis. This narrative review synthesizes evidence obtained before orchiectomy and, where explicitly identified, broader pretreatment or pre-gonadotoxic evidence. Pre-orchiectomy studies generally report reduced sperm concentration, total sperm count, and progressive motility, together with impaired Sertoli and Leydig cell function. Tumor-derived human chorionic gonadotropin (hCG) can mask reduced Leydig reserve; in hCG-negative men, research-derived testosterone-to-luteinizing hormone and calculated free testosterone-to-luteinizing hormone ratios may aid risk stratification but lack standardized diagnostic cutoffs. Proposed contributors include testicular dysgenesis, contralateral impairment, germ cell neoplasia in situ, local tumor effects, and oxidative or proteomic alterations, although evidential support varies. These findings support fertility counseling at diagnosis, sperm cryopreservation before orchiectomy when feasible without delaying treatment, selected use of onco-microTESE when no usable ejaculate is available, and hCG-aware endocrine follow-up. Full article

The continual spermatogenesis throughout adulthood is ensured by a rare and unique cell group named spermatogonial stem cells (SSCs), which undergo self-renewal and/or differentiate into sperm cells. SSCs also become a promising genetic source for the protection of animal biodiversity. However, the isolation and culture of SSCs in vitro is still a big challenge and poorly explored in rabbits. The main objective of this study was to isolate, culture, and deeply characterize SSCs obtained from rabbit testes. Briefly, rabbit testicular tissue was mechanically and enzymatically dissociated, and obtained testicular somatic and germ cells were cultured for a short term in culture media supplemented with specific molecular factors maintaining SSC self-renewal and proliferation (GDNF, GFRα-1, FGF2, etc.). Immunofluorescent and PCR techniques were used for molecular profiling of cultured SSCs, while TEM analysis revealed their ultrastructure. After a few weeks, round and grape-like SSC colonies emerged, growing on the feeder cell layer. Rabbit SSCs showed positive staining for DBA, GFRA1, PLZF, RET, PGP9.5, DAZL, and DDX4. Increased expression of additional SSC markers was noticed using RT-qPCR and dd PCR (RET, PLZF, PGP9.5, DAZL, DDX4, CDH1, CD9, CD14, CD90, c-kit, ALDH, SSEA-4, SALL4, OCT4, and SOX2), while ultrastructure typical for primitive undifferentiated cells was observed under TEM. In conclusion, we successfully established a method for rabbit SSC isolation, culture, and phenotyping, which might facilitate their collection for further cryopreservation. However, the self-renewal, proliferative, and differentiation capacities of cultured SSCs still need to be confirmed through an in vivo SSC transplantation experiment. Full article

Yaks are indigenous livestock species of the Qinghai–Tibet Plateau. Due to long-term exposure to extreme environmental stressors, including high altitude, hypoxia, and low temperatures, its male reproductive system has evolved distinct adaptive strategies. Specifically, testicular weight is markedly lower than that of cattle. Nevertheless, according to reported data from different experiments, although its single ejaculate volume is lower than that of Tibetan cattle, it can still maintain comparable fresh sperm motility. These reproductive phenotypes make the yak an ideal model organism for investigating plateau adaptation and sperm energy metabolism. The present review synthesizes continuous molecular events in yak testes spanning embryonic development through senescence. It focuses on dissecting the core regulatory networks governing spermatogonial stem cell self-renewal, meiosis, and spermiogenesis. It integrates the latest advances in testicular microenvironment dynamics and epigenetic modifications. Additionally, male sterility in cattle-yak serves as a natural mutant model. Essential regulatory modules governing spermatogenesis can be inferred from its spermatogenic-arrest phenotype. Nevertheless, comparative omics analyses between yaks and cattle are confounded by seasonal variation and differing genetic backgrounds. It is therefore critical to distinguish signatures driven by genetic adaptation from those arising from environmental plasticity. Finally, this paper presents research prospects regarding how to utilize single-cell multi-omics and gene-editing technologies to deeply dissect the underlying mechanisms of plateau reproductive adaptation to provide theoretical support for improving yak fecundity and hybrid breeding. Full article

Introduction: Male infertility is a complex global health challenge, with emerging evidence suggesting that vitamin D plays a pivotal role in testicular function and spermatogenesis. This systematic review and meta-analysis aimed to evaluate the impact of vitamin D supplementation on semen parameters and reproductive hormones in infertile men. Methods: A comprehensive search of electronic databases (PubMed, Cochrane Library, and Web of Science) was conducted to identify randomized controlled trials (RCTs) investigating vitamin D supplementation in infertile males. Primary outcomes included Follicle-Stimulating Hormone (FSH), total testosterone, and Sex Hormone-Binding Globulin (SHBG). Secondary outcomes focused on semen quality, specifically volume, concentration, and motility. Data were pooled using fixed-effects or random-effects models based on heterogeneity (I²). Results: Analysis of six trials (n = 696) revealed that vitamin D supplementation significantly increased total testosterone levels compared to controls (SMD: 0.38; 95% CI: 0.13, 0.62; p = 0.002), with no statistical heterogeneity (I² = 0%). In contrast, no significant differences were observed for FSH (SMD: 0.01; 95% CI: −0.28, 0.29; p = 0.96) or SHBG (SMD: 0.95; 95% CI: −0.12, 2.02; p = 0.08). For semen parameters, supplementation was associated with notable improvements in sperm concentration and progressive motility, whereas semen volume remained largely unchanged across the included studies. High heterogeneity in SHBG results (I² = 91%) suggests that individual study characteristics, such as baseline vitamin D deficiency, may influence hormonal responses. Conclusions: Vitamin D supplementation selectively enhances endocrine function by increasing testosterone levels and improves functional semen parameters in infertile men. These findings support the use of vitamin D as a cost-effective adjuvant therapy, though its impact on definitive fertility outcomes, such as live birth rates, requires further large-scale clinical investigation. Full article

Background: Butyrophenone neuroleptics are used in veterinary practice—haloperidol in the capture and translocation of wild ungulates, azaperone in swine—and antipsychotics prescribed to owners are a recognised cause of accidental toxicosis in dogs and cats. Organ-level toxicity data for this drug class are nonetheless almost absent in any species. Intravenous lipid emulsion (ILE) is an established antidote in small-animal emergency medicine for lipophilic intoxications, but the veterinary evidence base consists of case reports with clinical endpoints, and no controlled study has examined what ILE does to the tissues themselves. This study used an acute rodent overdose model to provide that organ-level assessment. Methods: Forty male Wistar albino rats were randomised to four groups of ten: control (saline 2 mL/kg oral gavage), HP (17.5 mg/kg oral gavage), HP + ILE (17.5 mg/kg HP plus 20% ILE 7.5 mL/kg intravenously at 0.5 h and 8 h, an empirical regimen) and ILE alone. Endpoints were assessed at 24 h. Seventeen histopathological parameters across seven organs were scored semi-quantitatively by a blinded pathologist (n = 10 per group), with independent re-scoring of a stratified random 30% subsample by a second blinded pathologist. Serum total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI) and routine biochemistry were measured in animals with adequate serum (n = 34 and n = 35). Comparisons used Kruskal–Wallis and Mann–Whitney U tests with Benjamini–Hochberg false discovery rate (FDR) control. Results: Haloperidol produced significant injury in the liver, kidney, brain and testis (all p < 0.001 vs. control) and mild histological cardiac changes (degeneration p = 0.014; congestion p = 0.034); lung and eye were unaffected. Serum urea was markedly elevated in HP (67.4 ± 13.2 vs. 46.5 ± 8.8 mg/dL; p = 0.001, d = 1.82) and HP + ILE (61.5 ± 8.7 mg/dL; p = 0.003), with unchanged creatinine, and correlated strongly with renal histopathology (renal inflammation vs. urea ρ = 0.74, p < 0.001). ILE significantly attenuated histopathological injury in 8 of the 12 haloperidol-associated parameters after FDR correction (renal congestion q = 0.032, r = 0.70; testicular Johnsen score q = 0.032, r = 0.66); the testicular score improved significantly relative to HP (q = 0.032) but remained statistically indistinguishable from control (p = 0.072), which does not establish equivalence. ILE did not reduce serum urea (HP + ILE vs. HP, p = 0.26) and did not modify the mild histological cardiac changes (p ≥ 0.40); no functional or electrophysiological cardiac endpoint was assessed. No group difference was detected in serum TOS or OSI (p = 0.43 and p = 0.51), whereas TAS was significantly reduced in the ILE-alone group (p = 0.011); the biological interpretation of this TAS finding remains uncertain, because interference of residual lipaemia with the spectrophotometric assay could not be excluded and would also propagate to the derived OSI. No tissue oxidative marker was measured. Transaminases were not elevated by haloperidol and showed no correlation with hepatic histopathology (|ρ| ≤ 0.17, all p > 0.34). ILE alone caused no histopathological abnormality at this dose and time point. Inter-observer agreement was high (95.6% exact agreement; median weighted κ = 0.893). Conclusions: In this acute overdose model, ILE is associated with a differential and structurally incomplete histopathological response: microscopic injury improves in four organs while renal function does not, and the mild histological cardiac changes are unaltered. Serum transaminases did not reflect concurrent organ-level injury at 24 h. Serum TOS and OSI showed no detectable group differences, while TAS was reduced in the ILE-alone group with an uncertain biological interpretation. Given the analytical uncertainty and the limited sample size, these indices provided no usable surrogate information about organ-level injury in this model. These findings define which organ systems respond and require confirmation in target veterinary species before informing clinical practice. Full article

Alpha-1 adrenergic receptor antagonists are widely used in the management of lower urinary tract symptoms, where they can induce ejaculatory dysfunction as a pharmacodynamic effect, particularly with α1A-selective agents. This observation has led to growing interest in their potential role as non-hormonal male contraceptives. This narrative review evaluates current clinical and preclinical evidence regarding the impact of α-blockers on the ejaculatory mechanism, with a focus on their potential application in male contraception. Both human and animal data were examined to contextualize the mechanistic basis for contraceptive potential. Evidence from clinical and pharmacological studies indicates that inhibition of α1-adrenoceptor-mediated smooth-muscle contraction in tissues involved in seminal emission, including the vas deferens, seminal vesicles, and prostate, can impair the emission phase of ejaculation. Agents such as tamsulosin and silodosin have been reported to induce anejaculation or markedly reduce semen volume, providing pharmacodynamic evidence of impaired seminal emission; however, these effects should not be considered equivalent to demonstrated contraceptive efficacy. Prospective clinical evidence currently includes one prospective pilot study and one randomized placebo-controlled clinical trial evaluating silodosin as a potential reversible non-hormonal male contraceptive. The prospective evidence includes marked and progressive suppression of sperm output and semen volume with repeated silodosin administration; at week 12, 94% of participants achieved a total sperm count ≤ 1 × 10⁶ per ejaculate, while the observed pregnancy incidence was 4% versus 17% with placebo. However, the available evidence remains insufficient to establish reliable contraceptive effectiveness for individual sexual exposures. Safety considerations, including cardiovascular effects and sexual dysfunction, also remain insufficiently characterized in healthy men. α1-adrenoceptor antagonists represent a biologically plausible pharmacologic strategy for male non-hormonal contraception by interfering with seminal emission and sperm delivery without directly suppressing spermatogenesis. Further pharmacokinetic–pharmacodynamic studies and rigorously designed multicentre clinical trials are required to determine the optimal dosing strategy, completeness and consistency of seminal emission suppression, contraceptive effectiveness, safety, acceptability, and reversibility of this approach. Full article

Sertoli cells (SCs) are essential for spermatogenesis and provide structural and nutritional support to germ cells in the Chinese Holstein cattle testis. Although microRNAs (miRNAs) are known to regulate SC function, the specific role of Bta-miR-146a in bovine SCs is unclear. This study investigated the mechanisms by which Bta-miR-146a regulates bovine immature SCs. Using molecular cloning, we constructed Bta-miR-146a overexpression and interference vectors and transfected them into SCs via lipofection. Quantitative real-time PCR (RT-qPCR), 5-ethynyl-2′-deoxyuridine (EdU) proliferation assays, Cell Counting Kit-8 (CCK-8) viability assays, and flow cytometry revealed that Bta-miR-146a overexpression inhibited SC proliferation and promoted apoptosis, whereas Bta-miR-146a inhibition increased proliferation and suppressed apoptosis. Dual-luciferase reporter assays confirmed that SMAD4 is a direct target of Bta-miR-146a; SMAD4 interference reduced SC proliferation and increased apoptosis, whereas overexpression had the opposite effect. Furthermore, activity of this gene modulates the TGFβ/MAPK signaling pathway; SMAD4 interference reduces the expression of TGFβ, TGF-βRII, DAXX, MAP3K5, P38, and MAX. These findings indicate that the Bta-miR-146a/SMAD4/TGFβ/MAPK axis is a key regulator of SC proliferation and apoptosis, offering insights into the molecular mechanisms underlying bovine spermatogenesis and potential targets for improving reproductive performance. Full article

Cyanobacterial harmful algal blooms have increased globally, likely in part due to climate change and anthropogenic eutrophication, elevating exposure of humans and other terrestrial and aquatic animals to cyanotoxins through drinking water, food chains, and recreational activities. Microcystin-LR (MC-LR), the most prevalent microcystin congener, is well known for its hepatotoxicity, yet accumulating evidence indicates that it also exerts reproductive and developmental toxicity in mammals. This review summarizes recent experimental and epidemiological studies indicating that MC-LR disrupts reproductive function through direct cellular injury to germ and somatic cells, dysregulation of gonadal steroidogenesis, and impairment of the hypothalamic-pituitary-gonadal (HPG) axis. In males, MC-LR disrupts spermatogenesis and sperm quality, while in females it impairs oocyte competence, uterine receptivity, and placental function, leading to adverse pregnancy outcomes. Importantly, exposure during critical developmental windows can influence developmental trajectories and contribute to long-term, multi-organ dysfunction in offspring via endocrine imbalance and epigenetic reprogramming. Mechanistically, MC-LR toxicity involves convergent oxidative stress, mitochondrial dysfunction, inflammatory signaling, DNA damage, and chromatin remodeling. Collectively, these findings indicate that reproductive and developmental toxicity should be considered in assessments of the health risks associated with MC-LR and support the incorporation of reproductive endpoints into human health and ecological risk assessment frameworks. Full article

This study investigated the pathological processes by which two Salmonella strains induce orchitis and impair spermatogenesis in mice, with emphasis on inflammation and blood–testis barrier (BTB) integrity. Thirty male Kunming mice were randomly assigned to the human-derived Salmonella enterica serovar Enteritidis H71 group, the sheep-derived Salmonella enterica serovar Agona W42 group, or the phosphate-buffered saline control group (n = 10 per group). An acute orchitis model was established by intrascrotal injection. Histopathological examination revealed marked testicular and epididymal lesions, disruption of the spermatogenic epithelium, and reduced sperm abundance in infected mice. Transcriptomic analysis identified 4546 differentially expressed genes shared by the two infected groups and showed enrichment of the Toll-like receptor (TLR), nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) signaling pathways. Real-time quantitative PCR further showed increased expression of interleukin 6 (Il6), interleukin 1 beta (Il1b), and tumor necrosis factor (Tnf), accompanied by reduced expression of tight junction protein 1 (Tjp1), occludin (Ocln), and synaptonemal complex protein 3 (Sycp3) in infected mice (p < 0.05), except for Tjp1 in the W42 group. These findings indicate that Salmonella-induced inflammatory activation is associated with BTB disruption and impaired spermatogenesis, providing a basis for further investigation of bacterial orchitis and zoonotic reproductive risks. Full article

Type 1 diabetes (T1D) is a systemic metabolic disorder associated with male reproductive dysfunction. Given the pivotal role of actin cytoskeleton remodeling in spermatogenesis and sperm function, this study investigated the effects of T1D on actin-regulating pathways in rat testis and spermatozoa (SPZ). Adult Wistar rats were rendered diabetic by streptozotocin administration (65 mg/kg, i.p.). Testicular analysis revealed a reduced F-/G-actin ratio together with marked F-actin disorganization, consistent with altered actin cytoskeleton remodeling. To investigate the molecular mechanisms underlying these alterations, key regulators of actin dynamics were examined. Diabetic animals displayed impaired expression of EPS8, Fascin, N-WASP, and the ARP2/3 complex, suggesting altered regulation of actin assembly, bundling, and branching. Further analyses demonstrated dysregulation of signaling pathways governing cytoskeletal organization. Reduced levels of phosphorylated Disheveled-2, DAAM1, RhoA-GTP, and ROCK1 indicated impairment of the planar cell polarity pathway. In parallel, changes in LIMK1/cofilin phosphorylation supported abnormal regulation of actin filament turnover. Alterations in the RICTOR/PKC/MARCKS signaling pathway further highlighted defects in cytoskeletal control. Similar abnormalities were observed in mature SPZ, where altered F-actin distribution and DAAM1 localization suggested persistent cytoskeletal defects. Moreover, diabetic SPZ exhibited a reduced ability to undergo acrosome reaction, accompanied by altered MARCKS phosphorylation, highlighting defects in actin-dependent processes essential for sperm function and fertilizing capacity. These findings indicate that disruption of actin cytoskeleton dynamics may represent a major mechanism contributing to testicular and sperm abnormalities in T1D, providing new insights into the mechanisms underlying diabetes-associated male reproductive dysfunction. Full article

Reliable evaluation of testicular toxicity in nonclinical safety studies requires animals with sufficient histological testicular maturity. However, chronological age alone is an unreliable indicator of reproductive maturity in cynomolgus macaques because substantial inter-individual variation exists in pubertal development. Since histological maturity can only be confirmed after necropsy, a practical, non-invasive method for prospective animal selection is needed. This retrospective study evaluated whether in-life testicular volume could predict histological maturity suitable for routine histopathological evaluation. Testicular length and width were measured immediately before scheduled necropsy in 61 male cynomolgus macaques (Macaca fascicularis) using digital calipers, and testicular volume was calculated using the ellipsoid formula. Histological maturity was classified according to the six-grade system of Haruyama et al., with bilateral Grade ≥4 selected as the primary endpoint because this represents the earliest stage at which routine histopathological evaluation of spermatogenesis is considered reliable. Logistic regression and receiver operating characteristic (ROC) analyses demonstrated a strong association between mean testicular volume and bilateral Grade ≥4 status (AUC = 0.976), with an optimal ROC-derived cut-off value of approximately 8.7 cm³. Although age and body weight were significantly associated with histological maturity, testicular volume remained an independent predictor after adjustment for these variables. Testicular width also showed high diagnostic performance, whereas postmortem indices, including testicular weight and the mean relative testicular weight, cannot be applied for prospective animal selection. These findings suggest that externally measured testicular volume may facilitate prospective identification of animals likely to possess testes suitable for routine histopathological evaluation before study initiation. Full article

Bisphenols and phthalates are ubiquitous endocrine-disrupting chemicals with potential effects on reproductive neuroendocrine regulation, particularly during sensitive developmental windows. This review summarizes current evidence on their exposure profile, mechanisms of reproductive disruption, and female- and male-specific reproductive adversities. A structured narrative review was conducted using PubMed/MEDLINE, Scopus, and Web of Science, including experimental, epidemiological, biomonitoring, systematic review, and meta-analytic studies addressing bisphenols, phthalates, fertility, hormonal regulation, gametogenesis, pregnancy outcomes, and reproductive toxicity mechanisms. Bisphenols and phthalates interfere with estrogenic and androgenic signaling, hypothalamic–pituitary–gonadal axis regulation, steroidogenesis, oxidative stress, inflammation, apoptosis, mitochondrial function, and epigenetic regulation. Reported outcomes include impaired ovarian function, altered oocyte development, hormonal imbalance, reduced semen quality, defective spermatogenesis, sperm DNA damage, infertility, and adverse developmental or pregnancy-related effects. However, human evidence remains heterogeneous and limited by observational designs, exposure misclassification, residual confounding, and insufficient mixture assessment. Current evidence supports biological plausibility for bisphenol- and phthalate-related reproductive toxicity, but causal inference remains limited. Prospective studies with repeated biomonitoring, standardized reproductive endpoints, sex- and age-specific analyses, and improved mixture modeling are needed. A precautionary reduction in avoidable exposure appears reasonable, particularly during sensitive reproductive and developmental periods. Full article

Rare earth elements (REEs) are increasingly recognized as modulators of male reproductive health. This review presents the first comprehensive and critical analysis of the detrimental and potentially beneficial effects of REEs on male vertebrate reproductive function. In vivo and in vitro studies show that elements, particularly Gadolinium, Lanthanum, and Yttrium, share a toxicological profile characterized by oxidative stress, inflammation, mitochondrial dysfunction, endocrine disruption, and impairment of the blood–testis barrier. These mechanisms converge on both somatic and germ cell populations, ultimately compromising spermatogenesis and hormonal balance. Limited epidemiological data in humans are consistent with experimental findings, indicating inverse associations between seminal REE levels and sperm quality. CeO₂ nanoparticles represent an exception, showing dose-dependent duality: although some murine studies describe toxic effects, a broader and more consistent body of evidence indicates their protective action by restoring testicular homeostasis in diabetic models, in rats exposed to pesticides, pharmacological agents or irradiation, and in in vitro-treated spermatozoa. Preliminary data on Yttrium (YO) and Gadolinium (GdVO₄) nanoparticles similarly point to protective effects under pathological conditions, whereas Neodymium and Samarium show reproductive toxicity, including hormonal disruption and impaired sperm quality. Overall, REEs cannot be considered a homogeneous class: some pose reproductive hazards, others show potential biomedical utility. A systematic, mechanistic research framework is needed to resolve these dualities. It should contextualise reproductive risks in relation to the growing environmental and occupational exposure to REEs, while simultaneously exploring the biomedical potential of those elements that exhibit protective profiles. Full article