Search Results (1,062)

Tri-o-cresyl phosphate (TOCP) is widely used as a plasticizer, flame retardant, and lubricant additive, but has been reported to impair spermatogenesis. However, how TOCP affects spermatogenesis remains unclear. Therefore, the objective of this study is to investigate the underlying mechanism by which TOCP disrupts spermatogenesis. In order to achieve this, adult male mice were orally administered TOCP at doses of 0, 200, or 400 mg/kg for two weeks, and we found that TOCP exposure reduced the number of germ cells and decreased sperm density. Moreover, the numbers of PCNA-positive cells and phospho-histone H3 (Ser10)-positive cells in mouse testicular tissues were significantly decreased following TOCP treatment, indicating that germ cell proliferation may be impaired. In addition, TOCP did not affect the protein expression of neuropathy target esterase (NTE) in testicular tissues but markedly inhibited its enzymatic activity (by approximately 30% relative to the control level). In vitro experiments further demonstrate that TOCP suppressed cell proliferation and mitotic progression in mouse GC-1 spg cells and excessively activated endoplasmic reticulum (ER) stress. Treatment with 4-phenylbutyric acid (4-PBA), an ER stress inhibitor, partially reversed the TOCP-induced inhibition of cell proliferation and mitosis. Furthermore, TOCP inhibited NTE activity in GC-1 spg cells, and NTE knockdown produced a phenotype similar to that observed after TOCP exposure, characterized by suppressed cell proliferation and mitotic progression. Surprisingly, ER stress was not activated in GC-1 spg cells following NTE knockdown. Collectively, these findings suggest that TOCP may impair spermatogenesis by inhibiting the proliferation and mitotic progression of mouse germ cells, potentially through mechanisms involving excessive activation of ER stress or suppression of NTE activity. Full article

Aging and stress-related factors affect sperm DNA methylation in regions associated with genes responsible for embryonic development. The stochastic epigenetic variation hypothesis holds potential to explain these patterns, proposing that, in response to stressors, naturally variable methylation regions (VMRs) associated with morphogenetic genes exhibit increased methylation variation to diversify phenotypes and improve the chances of survival of the genetic lineage. Here, we test predictions from this hypothesis using mouse and rat sperm DNA methylation data from publicly available sources. Specifically, we identify VMRs and analyze their overlap with regions differentially methylated (DMRs) in response to aging, stressors, and with various genomic elements. We demonstrate that the nature of the DNA regions, rather than the nature of the stressor, determines the response of the sperm methylome to aging and stress, and propose a model that explains shifts in methylation within VMRs through stochastic changes, whereby initially hypermethylated regions lose methylation and initially hypomethylated regions gain methylation. VMRs are depleted of open chromatin regions and histones in male germ cells and are enriched for a binding motif for ZFP42, an epigenetic remodeler. This knowledge may open opportunities for the development of interventions to control epigenetic information transfer via germ cells. Full article

As the hybrid offspring of cattle and yak, cattle–yaks suffer from male sterility, manifesting as cascading spermatogenic failure. Despite the Y chromosome’s pivotal role in spermatogenesis, the absence of a high-quality yak Y assembly has long impeded mechanistic understandings from this perspective. Here, a near-complete 42.4 Mb yak Y chromosome is constructed through a multi-stage assembly strategy that integrates de novo assembly with pangenome graph construction and Hi-C guided refinement. By developing a rigorously standardized gene annotation pipeline for precise cross-species comparison, we find that yaks have undergone a greater expansion of Y-linked ampliconic genes than cattle. Integrating this ampliconic landscape with short-read and full-length transcriptomics further demonstrates that yaks exhibit a drastic 2-to-4-fold increase in transcriptionally active copies of spermatogenesis-related ampliconic genes (including TSPY1, ZNF280BY, HSFY and PRAMEY) relative to cattle. Given negligible homology outside the pseudoautosomal region and conservation of key meiotic proteins, we propose a ‘cis-trans regulatory mismatch’ model driven by divergent Y-linked amplification as a working hypothesis to explain the primary genetic mechanism of cattle–yak male sterility. Together, these findings offer critical insights for addressing cattle–yak male sterility and establish the Y chromosome as an active driver of reproductive isolation beyond its traditional degenerate characterization. Full article

Castration is widely used in goat production to improve meat quality and manage reproduction, yet conventional surgical methods raise significant animal welfare concerns. Immunocastration targeting gonadotropin-releasing hormone (GnRH) offers a promising, welfare-friendly alternative, but its efficacy in slow-growing indigenous breeds remains poorly defined. In this study, we developed a novel tandem-repeat GnRH(30) recombinant vaccine and evaluated its effects on growth performance, reproductive function, and meat quality in male Leizhou goats. Eighteen six-month-old bucks were assigned to an immunocastration group (IM), surgical castration group (SC), or intact control group (IC). Vaccinated goats produced sustained anti-GnRH antibodies and exhibited significantly suppressed testosterone levels comparable to surgical castrates. Immunocastration induced marked testicular atrophy, disrupted spermatogenesis, reduced semen volume and sperm motility, and increased sperm abnormalities. Importantly, early growth performance and final body weight were not significantly affected. Compared with intact males, both IM and SC goats showed improved meat quality traits, including reduced drip loss and shear force, accompanied by increased intermuscular fat deposition, with overall patterns in the IM group closely resembling those of surgical castration. Overall, these findings indicate that the GnRH(30) vaccine can effectively suppress spermatogenesis and improve meat quality without affecting growth, providing an effective technical approach for castration management in indigenous goats. Full article

Spermatogenesis is a metabolically intensive process that is highly sensitive to perturbations in proteostasis. The integrated stress response (ISR) and its central effector, ATF4, orchestrate adaptive responses to maintain cellular homeostasis under stress; however, the functional significance of ATF4 in mammalian spermatogenesis has not been established. To investigate this, we engineered a conditional knockout mouse model with germ cell-specific deletion of the Atf4 gene. Results showed that Atf4 deletion did not impair spermatogenesis or male fertility, with knockout mice exhibiting normal testicular histology and standard sperm parameters. Proteomic analysis, however, revealed that ATF4 contributes to testicular protein expression homeostasis, as its deficiency caused marked dysregulation of the testicular proteome, especially impacting SQSTM1/p62 downregulate through endoplasmic reticulum (ER) stress pathway. We conclude that ATF4’s role in regulating proteostatic balance is functionally decoupled from its necessity for the core progression of spermatogenesis. These findings define ATF4 as a potential resilience agent safeguarding testicular function under ER stress, rather than a direct regulator of male germ cell development. Full article

Oxidative stress and environmental factors impair spermatogenesis and testicular function. The gut–testis axis has emerged as an important regulator of male reproductive health, influencing spermatogenesis beyond traditional endocrine control. This study evaluated the efficacy of a combination of Carob (Ceratonia siliqua), Bifidobacterium longum GA24, and ribonucleotides (MIX) on in vitro models of the gut–testis axis (co-culture Caco-2/HSerC on Transwell^® system). At the intestinal level, MIX increased Caco-2 cell viability, improved tight junction levels, regulated ROS production, and increased butyrate synthesis beyond physiological values, highlighting improved intestinal barrier function and integrity. In the gut–testis model, HSerC cells subjected to H₂O₂ 300 μM showed 1.5-fold increased viability, 81% reduction in ROS, increased ATP (+1.7-fold) and NO (+1.8-fold). The MIX combination reduced the apoptotic markers BAX (−1.6-fold), caspase-3 (−1.84-fold), and Cyto-C (−1.52-fold), and the inflammatory mediators TNFα and IL-6. MIX enhanced Sertoli cell maturation markers, increasing AR by 6-fold, p27 by 1.64-fold, and SGP-2 by 2.5-fold, and modulated hormonal-related markers by increasing testosterone and FSHR expression. These findings indicate that MIX may positively modulate the gut–testicular axis, supporting the intestinal barrier, testicular health, and spermatogenesis. Full article

This study investigates whether long-term global warming is associated with fertility decline across 195 countries from 1960 to 2023, and whether this relationship varies by economic development and adaptive capacity. We analyze Total Fertility Rate (TFR) data from the World Bank alongside temperature anomaly measures from NOAA and NASA using Pearson correlations and ordinary least squares (OLS) regression models. Regional analyses include Africa, Asia, Europe, the Middle East, and the Arctic, with GDP per capita serving as a proxy for economic development and adaptive capacity. Globally, temperature anomalies and fertility exhibit a strong negative correlation ($r\approx -0.90$, $p<0.001$). However, substantial regional heterogeneity emerges after controlling for GDP. In Africa ($r=-0.89$) and the Middle East, temperature anomalies remain statistically significant predictors of fertility decline even after GDP adjustment ($\beta =-0.99$, $p<0.001$; $\beta =-1.27$, $p<0.001$, respectively). In contrast, temperature effects become statistically insignificant in South Asia, East Asia, Europe, and the Arctic once GDP is controlled, indicating that fertility decline in these regions is driven primarily by socioeconomic modernization rather than climatic stress. These findings suggest that global warming functions as a conditional demographic stressor whose impact depends critically on adaptive capacity. In regions with limited infrastructure, including constrained access to air conditioning, healthcare, and occupational heat protection, rising temperatures remain significant predictors of fertility decline, potentially mediated through heat-sensitive biological mechanisms such as impaired spermatogenesis. By contrast, in higher-income regions, high adaptive capacity appears to buffer reproductive systems from thermal stress, allowing socioeconomic factors to dominate fertility dynamics. Full article

Male fertility is declining worldwide, with notable reductions in sperm counts, emphasizing the need for new therapeutic interventions. Atranorin (ATR), a lichen-derived secondary metabolite, exhibits strong antioxidant and anti-inflammatory activities. This study assessed the protective effects of ATR on type 1 diabetes (T1D)-induced reproductive dysfunction in rats. T1D was induced in male Wistar rats via a single intraperitoneal injection of alloxan at 150 mg/kg body weight (bw). ATR significantly ameliorated T1D-related reproductive damage. At 170 mg/kg bw, ATR reduced hyperglycemia by 66% and attenuated seminal inflammation, decreasing leukocyte infiltration (−51%) and myeloperoxidase (MPO) activity (−68%). Oxidative balance improved, as evidenced by increased total antioxidant status (TAS) (+203%) and decreased thiobarbituric acid reactive substances (TBARS) (−73%), hydrogen peroxide (H₂O₂) (−45%), and total oxidant status (TOS) (−70%). Steroidogenesis was restored through enhanced 3β-hydroxysteroid dehydrogenase (3β-HSD) (+65%) and 17β-hydroxysteroid dehydrogenase (17β-HSD) (+102%) activities, resulting in a 90% recovery of testosterone levels. Seminal plasma function improved, with increased fructose levels (+71%), normalized pH (7.4), and enhanced hyaluronidase (HYAL) (+71%), adenosine triphosphatase (ATPase) (+71%), and prostatic acid phosphatase (PAP) (+79%) activities. Fertility biomarkers, such as adenosine deaminase (ADA) (+148%) and lactate dehydrogenase-C4 (LDH-C4) (+62%), increased, and essential minerals Zn²⁺ (+72%), Ca²⁺ (+96%), Mg²⁺ (+84%), and Se (+57%) were restored. Consequently, sperm density (+87%), viability (+69%), and motility (+189%) improved, while abnormalities declined (−46%). Histological findings confirmed the restoration of spermatogenesis and epididymal maturation. ATR effectively counteracts diabetes-induced reproductive dysfunction by reducing oxidative and inflammatory stress while improving hormonal and seminal parameters. Full article

Male infertility contributes to nearly half of infertile couples, with asthenozoospermia and oligoasthenoteratozoospermia as predominant factors. Despite advancements in sperm processing techniques, the outcomes remain limited in severe cases, particularly concerning motility, mitochondrial function, and DNA integrity. Platelet-rich plasma (PRP), an autologous concentrate rich in platelets (>1 × 10⁶/μL) and growth factors, has recently gained attention as an adjunctive therapy in andrology and assisted reproduction. This review systematically evaluated studies published between 2015 and 2025 investigating PRP use in sperm processing, including in vitro experiments, clinical trials, animal models, and mechanistic studies. PRP demonstrated concentration-dependent benefits, with 5% PRP yielding optimal improvements: motility increased by 15–30%, mitochondrial activity increased by up to 80% (p = 0.002), and oxidative stress was significantly reduced (p < 0.001). PRP’s effects on DNA integrity differ by application method: intratesticular administration improves spermatogenesis, producing sperm with reduced DNA fragmentation (~33% relative reduction after 3 months, p < 0.001), while in vitro supplementation provides limited protection against processing-induced damage. Mechanisms involve antioxidant action, mitochondrial protection via AMP-activated protein kinaseNuclear Factor kappa-light-chain-enhancer of activated B cells (AMPK/NF-κB) modulation, membrane stabilization, and the selective preservation of higher-quality spermatozoa. PRP shows consistent biological efficacy and safety but lacks methodological standardization. Fewer than 20% of studies report platelet concentrations, limiting reproducibility. Standardized protocols distinguishing leukocyte-poor from leukocyte-rich preparations and randomized trials focusing on live birth rates are recommended. This review proposes an eight-point characterization checklist for future research. Full article

Male infertility, a global health issue marked by spermatogenic failure, hinges on selenium (Se) as a key element for normal spermatogenesis. Among different Se species, Se-methylselenocysteine (MeSeCys) has been developed as a natural organic Se supplement with potent antioxidant and anti-inflammatory properties, but its direct effects on male reproduction need to be further explored. This study investigated the effect of MeSeCys on GC-1 spg (GC-1) and GC-2 spd (ts) (GC-2) cell lines, which mimic early stages. Treatment with 75 μmol/L MeSeCys for 24 h markedly enhanced the viability of both cell lines, with a more pronounced effect observed in GC-1 than in GC-2 cells. Moreover, this study demonstrated that MeSeCys enters cells through SLC7A11 or LRP8 channels and elevates intracellular Se levels in both GC-1 and GC-2 cells, with higher levels observed in GC-1 cells. RNA sequencing (RNA-seq) and bioinformatics analysis revealed that MeSeCys may regulate selenocompound metabolism and the glutathione metabolism pathway in both cell lines, increasing their intracellular glutathione (GSH) levels. Importantly, in GC-1 cells, MeSeCys specifically modulates the mTOR pathway, which further modulates glutathione metabolism and intracellular redox balance. This finding provides novel insights into the beneficial effects of MeSeCys on male reproductive cells, highlighting its potential as a nutritional supplement for male reproductive health. Full article

Eisenia fetida is one of the soil invertebrates most used in ecotoxicological and ecopathological studies. To date, the potential contribution of naturally occurring parasites to the variability of ecotoxicological endpoints has been poorly investigated. In this study, we provide a detailed histological description of the male reproductive system of E. fetida and report the occurrence and histological alterations associated with Monocystis sp. infection in laboratory-reared individuals. Uninfected individuals exhibited complete spermatogenesis, with all developmental stages from spermatogonia to mature spermatozoa and normal sperm storage within the spermathecae. Meanwhile, infected earthworms displayed marked reproductive alterations, including reduced sperm production and diminished sperm retention within spermathecae. Multilayered encapsulations, inflammatory nodules and melanization were detected within the seminal vesicles, in contrast with the immunological evasion observed in Lumbricus terrestris. These findings suggest species-specific differences in immune response and indicate that Monocystis sp. infection can induce reproductive impairment and activate energy-consuming immune responses. Because these parasite-induced changes closely resemble pollutant-driven ecotoxicological effects, Monocystis infections may act as a potential bias in ecotoxicological studies. We therefore recommend implementing parasitological screening of laboratory cultures to ensure the reliability of studies employing E. fetida as a bioindicator. Full article

Background: Follicle-stimulating hormone (FSH)-based vaccines show the potential to disrupt spermatogenesis without disturbing sexual function and libido in males. Herein, we developed a novel FSH vaccine based on the tandem of a conserved 13-amino acid receptor-binding epitope of FSHβ (FSHβ13AA-T) and tested its effect on reproductive physiology and function using the male mouse as a model. Methods: Serum reproductive hormone levels, testicular histology, daily sperm production, sperm motility, libido and fertility of male mice following FSH vaccination were determined. Results: Compared to placebo-immunized controls, FSH vaccination triggered (p < 0.05) marked antibody generation, inhibited spermatogenesis and reduced sperm motility (p < 0.05), without adverse effects on serum LH and testosterone levels as well as the libido of male mice. Mechanistically, FSH vaccination suppressed (p < 0.05) testicular local estrogen production by downregulated aromatase encoding gene Cyp19a1 expression and also downregulated (p < 0.05) expression of key spermatogenic genes in testes, including Creb, INHα, Wnt2, Aqp8, Cmtm2a and Spata19, thus disrupting and impairing spermatogenesis and sperm motility. Conclusions: These results demonstrate that immunization of male mice against FSHβ13AA could substantially inhibit spermatogenesis and reduce sperm motility. Thus, FSHβ13AA-based vaccines hold potential for development as male contraceptives that do not compromise libido in species including men in which FSH is essential for spermatogenesis. Full article

Ubiquitination dynamically regulates critical cellular processes, including cell cycle progression, apoptosis, DNA repair, and chromatin remodeling. Deubiquitinating enzymes (DUBs) negatively regulate protein ubiquitination and are equally important for protein regulation in diverse biological processes. Spermatogenesis is a highly regulated process involving spermatogonia self-renewal and differentiation, ensuring continuous sperm production. Using a loss-of-function mouse model, several DUBs have been shown to be involved in spermatogenesis. In addition, specific genetic variants in the DUB genes have been associated with spermatogenic failure and male infertility. These studies provide strong evidence that DUBs are necessary for normal spermatogenesis and may influence male fertility. However, the exact mechanism by which these DUBs regulate spermatogenesis is still under investigation. The aim of this review is to highlight recent advances in the regulatory roles of DUBs in mammalian spermatogenesis and provide insight into the molecular mechanisms underlying their potential actions. An in-depth understanding of DUB-mediated regulation of spermatogenesis will provide a scientific rationale for the discovery and development of novel DUB-targeted therapeutic strategies for male infertility. Full article

Objective: Although Hu sheep are renowned for their high fecundity, the multi-tissue regulatory networks governing spermatogenesis, particularly within the hypothalamic–pituitary–testicular (HPT) axis, remain poorly understood. This study aimed to elucidate these mechanisms by performing a comparative proteomic analysis of the HPT axis in Hu sheep and three other breeds. Methods: We utilized data-independent acquisition (DIA) proteomics to analyze hypothalamic, pituitary, and testis tissues from 36 samples across four breeds. The experimental workflow included protein extraction, enzymatic digestion, LC-MS/MS, and subsequent bioinformatic analyses, complemented by histological examination. Results: Hu sheep exhibited accelerated testicular development and an earlier onset of spermatogenesis. Comprehensive proteomic profiling identified a total of 10,528 proteins, with 771 differentially expressed proteins (DEPs) detected in the testis. These testicular DEPs were significantly enriched in pathways related to spermatogenesis, the blood–testis barrier, and steroid hormone biosynthesis. Notably, the cAMP signaling pathway was consistently enriched across all three tissues, underscoring its pivotal role in regulating spermatogenesis. Protein–protein interaction (PPI) network analysis further highlighted hub proteins, such as MET, suggesting their potential involvement in somatic cell functions and the spermatogenic microenvironment. Key findings were validated by Western blot analysis. Conclusion: This study is the first multi-tissue proteomic investigation proposing a model in which the high reproductive performance of Hu sheep is potentially linked to the efficient, coordinated regulation of spermatogenesis-related proteins and signaling pathways—particularly in the testis. These findings offer novel insights into the molecular mechanisms of male reproduction in sheep and identify potential targets for future research and breeding applications. Full article

The blood–testis barrier (BTB) is a highly specialized and dynamic junctional structure formed by adjacent Sertoli cells that is essential for maintaining testicular immune privilege and supporting spermatogenesis. While the BTB undergoes tightly regulated, stage-dependent remodeling under physiological conditions, inflammatory stimuli can profoundly disturb this process. Accumulating evidence indicates that inflammatory conditions disrupt BTB integrity by altering junctional protein organization, cytoskeletal dynamics, and barrier permeability. We aimed to integrate current evidence to elucidate the key pathways by which inflammation impairs BTB integrity, drawing on studies using intratesticular administration of pro-inflammatory cytokines and experimental rodent models of reproductive dysfunction characterized by pathological inflammation, including chemotherapy-induced inflammation and orchitis. Collectively, findings from these models demonstrate that inflammatory signaling compromises BTB integrity, destabilizes the spermatogenic niche, and may contribute to impaired spermatogenesis. Our narrative review frames the BTB as a dynamic and inflammation-sensitive structure whose regulation emerges from the coordinated action of inflammatory pathways, cytoskeletal remodeling, and junction-associated signaling modules, rather than from isolated molecular events. Full article