Ali Soleimanzadeh

Semen preservation is a critical aspect of assisted reproductive technologies in canine breeding programs; however, oxidative stress during chilled storage negatively affects sperm quality by impairing motility, membrane integrity, and mitochondrial function. This study investigated the protective effects of apigenin and N-acetylcysteine amide (NACA), individually and in combination, on the quality, antioxidant defense system, and mitochondrial activity of canine spermatozoa stored at 5 °C for 72 h. Semen samples collected from five healthy mixed-breed dogs with proven fertility were pooled and diluted in a Tris-egg yolk extender supplemented with apigenin (0.2 or 0.4 mM), NACA (0.5 or 1 mM), or a combination of both (0.4 mM apigenin + 1 mM NACA). Sperm motility, membrane functionality, viability, DNA integrity, oxidative/antioxidant biomarkers, and mitochondrial parameters were evaluated at 0, 24, 48, and 72 h. Both antioxidants significantly improved all parameters compared with the control, with the combined treatment exhibiting the most pronounced and synergistic effects: motility and kinematic parameters approximately twofold higher, antioxidant enzyme activities markedly enhanced, lipid/protein oxidation reduced, and mitochondrial integrity and ATP production preserved after 72 h. In conclusion, the synergistic combination of apigenin and N-acetylcysteine amide significantly improves the quality and longevity of chilled canine spermatozoa, offering a promising strategy for optimizing semen extenders in canine breeding programs.

Dog semen conservation at cold temperatures (5 °C) is a valuable reproductive management tool, but it is bedeviled by issues of oxidative stress and mitochondrial damage that reduce sperm quality and viability. Urolithin A (UA), a natural metabolite derived from gut microbiota, has been found to be a molecule possessing strong antioxidant and mitochondrial protective activities. The objective of the study was to evaluate the protective effect of UA on the quality of dog sperm preserved in liquid form at 5 °C for 72 h. Semen samples were extended using a Tris-egg yolk extender supplemented with different concentrations of UA (0, 1, 5, and 10 µM). Evaluations were performed at 0, 24, 48, and 72 h of storage. The results showed that supplementation with 1 and 5 µM UA significantly preserved the total motility, progressive motility, and kinematic parameters (VCL, VSL, VAP). Furthermore, these doses significantly preserved sperm viability, plasma membrane integrity, and DNA integrity compared to the control group. Biochemically, UA enhanced the total antioxidant capacity (TAC), elevated the activity of key antioxidant enzymes (SOD, CAT, GPx), and reduced the markers of oxidative stress (MDA and H₂O₂). Concurrently, UA treatment preserved mitochondrial membrane potential (MMP), oxygen consumption rate (OCR), and intracellular ATP content. The 10 µM concentration was not effective in providing protective effects and acted similarly to the control. In conclusion, Urolithin A, particularly at an optimal concentration of 1 µM, may be capable of alleviating oxidative damage and preserving mitochondrial function, thereby being a potent supplement for canine semen extenders to enhance sperm quality and viability during refrigerated storage.

Heat exposure affects spermatogenesis and causes testicular injury through oxidative stress mechanisms. This study examined the preventive benefits of sesame seed oil (SSO) and α-lipoic acid (ALA), both powerful antioxidants, against heat-induced testicular damage. Thirty male Wistar rats were allocated into five groups ( n = 6 each): control (saline, no heat), heat stress (HS; 43 °C for 20 min/day for 60 days, saline), HS + ALA (100 mg/kg), HS + SSO (5 mL/kg), and HS + ALA + SSO. After 60 days, we examined the histology of the testicles, sperm parameters (concentration, motility, viability, morphology, and DNA integrity), oxidative stress markers, apoptotic gene expression, and fertility. These treatments enhanced sperm motility, viability, membrane integrity, and DNA stability while diminishing abnormalities. The levels of antioxidant enzymes (GPx, CAT, TAC, and SOD) and Bcl-2 increased, whereas the levels of pro-apoptotic markers (Bax and caspase-3/9), GSH depletion, MDA, and NO elevation decreased compared to those in the HS group (all p < 0.05). The SSO-ALA combination had synergistic effects, improving fertility parameters and alleviating histopathological damage. However, results may be confounded by experimental limitations such as anesthesia effects and lack of dose standardization. These results indicate that SSO and ALA may be effective treatments for heat stress-induced male infertility in animal models, though clinical translation requires further study.

The seminal microbiome, which is composed of different types of bacteria in semen and seminal plasma, has a significant impact on male reproductive health by changing the quality of semen and fertility. Previously regarded as sterile, the male reproductive tract contains microbes originating from the gastrointestinal tract, reproductive organs, and external sources such as sexual partners. Dysbiosis alters sperm parameters, triggers inflammation and oxidative stress, and is associated with conditions such as infertility, HPV infection, prostatitis, prostate cancer, and azoospermia. This systematic review adhered to the PRISMA 2020 guidelines (with 2025 extensions for reproducibility) and examined studies from PubMed, Scopus, and Science Direct (2015–2025, with prior context), concentrating on human, in vitro, and rodent models. Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes are among the most important phyla. Beneficial genera, such as Lactobacillus, improve sperm motility, concentration, and DNA integrity, whereas dysbiotic taxa, such as Prevotella, Pseudomonas, and Ureaplasma, are associated with declines. Sexual activity facilitates bidirectional microbial transfer, modifying diversity and fostering the dysbiosis. Inflammatory cytokines, reactive oxygen species, and metabolic disruptions are all involved in this process. Changes that are specific to a disease, such as higher levels of Fusobacterium in HPV-positive samples, worsen the situation. This review highlights how the microbiome alters sperm function and causes infertility. Standardized methods and long-term studies are needed to prove causality. Probiotics and other therapeutic interventions show promise in restoring balance and boosting fertility.

Background: Male infertility affects 8%–15% of couples, with male factors implicated in about half of cases; many remain idiopathic despite improved diagnostics. This narrative review addresses this gap by examining chronic inflammation as an underappreciated driver of sperm dysfunction that forms a bidirectional, self‐reinforcing cycle with oxidative stress (OS). Methods: We synthesized studies from 2015 to 2025 identified via PubMed, Scopus, and Web of Science, examining links between inflammation and OS, key immune pathways, and related risk factors through qualitative narrative synthesis. Results: Inflammation drives leukocyte infiltration, blood‐testis‐barrier breakdown, antisperm‐antibody production, and inflammasome activation, mechanisms that amplify OS and cause sperm DNA damage, impaired motility, apoptosis, and poor semen quality. Intrinsic factors (prostatitis, infection, varicocele) and extrinsic factors (obesity, aging, psychological stress) sustain this cycle through both ROS‐dependent and ROS‐independent, immune‐mediated pathways. Paternal inflammation may also induce epigenetic changes in sperm with potential consequences for offspring health. Conclusion: Antioxidant monotherapy alone is often insufficient when an underlying immune driver persists. Immune‐focused diagnostics combined with individualized, mechanism‐based treatment strategies may improve personalized care and fertility outcomes.

Chemical castration represents a non-surgical alternative to achieve male sterility by inducing azoospermia, with growing interest in nanoparticle-based agents owing to their targeted toxicity. This study aimed to determine whether intratesticular administration of copper oxide nanoparticles (CuO NPs) is effective in the chemical castration of male mice, and whether biochemical and histological changes can be assessed. Fifty-six adult male mice were divided into seven groups (n = 8 per group): a surgically castrated cohort, a control group, a sham group, and four experimental groups receiving CuO NPs at concentrations of 5, 10, 20, and 40 mg/mL. The assessment included fertility analysis after 30 days of treatment, sperm quality, testicular tissue, histological parameters, oxidative status, and gene expression. Testis weight, sperm parameters, and testosterone levels were significantly reduced by exposure to CuO NPs, but oxidative stress and DNA damage increased in a dose-dependent manner. Higher doses also decreased the expression of anti-apoptotic genes (Bcl-2) and increased that of pro-apoptotic genes (Bax and caspase-3). The correlation between these alterations and lower fertility indices highlighted the reproductive toxicity of CuO NPs. There were no noticeable differences between the control and sham groups for comparison. These findings suggest that intratesticular CuO NPs have potential as a method for chemical castration, offering a less invasive and more economical option for population-control applications.

This study investigated the dose-dependent effects of intratesticular zinc oxide nanoparticles (ZnO NPs) on reproductive toxicity in male Wistar rats, evaluating their potential as a chemical castration agent. Fifty rats, weighing 250–300 g and aged 12–14 weeks, were divided into five groups: control, sham (normal saline), and ZnO NPs at 5 mg/mL, 10 mg/mL, and 25 mg/mL. ZnO NPs (< 100 nm) were dissolved in saline and injected into the caudal testis. After 60 days, assessments included testicular oxidative stress markers (total antioxidant capacity [TAC], catalase [CAT], glutathione peroxidase [GPx], superoxide dismutase [SOD], malondialdehyde [MDA], nitric oxide [NO]), epididymal sperm parameters (count, motility, viability, morphology, DNA integrity, plasma membrane functionality), histopathological and morphometric evaluations (Johnsen/Cosentino scores, seminiferous tubule diameter [STsD], Sertoli cell index [SCI], repopulation index [RI], meiotic index [MI], Leydig cell nuclear diameter [LCND], tubular differentiation index [TDI], spermiogenesis index [SPI]), apoptosis-related gene expression (Caspase-3, Caspase-8, Caspase-9, Fas, Bcl-2 via quantitative real-time polymerase chain reaction [qRT-PCR]), and fertility indices post-mating. Results revealed dose-dependent impairments: reduced sperm concentration, motility, viability, and membrane integrity; increased DNA damage and morphological abnormalities; depleted antioxidants with elevated MDA/NO; severe histopathological changes including tubule atrophy and cell loss; upregulation of pro-apoptotic genes and downregulation of Bcl-2; and reduced fertility with higher implantation losses. While ZnO NPs exhibit beneficial effects, such as antioxidant and antimicrobial properties at low concentrations (typically < 5 mg/mL or 1–50 mg/kg in oral/intraperitoneal studies), they become toxic at higher doses (≥ 10 mg/mL in this intratesticular model), primarily through oxidative stress and apoptosis. These findings, despite species-specific and route-dependent variations, underscore ZnO NPs’ detrimental impact on spermatogenesis, emphasizing the need for cautious application to mitigate risks to male fertility.