Sperm Apoptosis Research Articles

Effect of natural astaxanthin on sperm quality and mitochondrial function of breeder rooster semen cryopreservation

Cryopreservation causes higher reactive oxygen species (ROS) concentrations, leading to oxidative stress and lipid peroxidation damage sperm, and using antioxidants can improve semen quality after freeze-thaw. Natural astaxanthin (ASTA) can be inserted into cell membranes and its antioxidant properties are stronger than other antioxidants. We aimed to investigate the effects of ASTA supplementation in the Beltsville Poultry Semen Extender (BPSE) on post-thaw rooster semen quality and to explore the potential mechanism of rooster semen quality change. The qualifying semen ejaculates collected from 30 adult male Jinghong No.1 laying hen breeder roosters (65wk old) were pooled, divided into four aliquots, and diluted with BPSE having different levels of ASTA (0, 0.5, 1, or 2μg/mL). Treated semen was cryopreserved and kept in liquid nitrogen. The entire experiment was replicated three times independently. Sperm viability, motility, curvilinear velocity, amplitude of lateral head displacement, straightness, plasma membrane integrity, and acrosome integrity were observed highest (P < 0.05) with 1μg/mL ASTA at freeze-thawing. Higher (P < 0.05) antioxidant enzyme (CAT-like, SOD) activities and free radical (·OH, O2.-) scavenging ability, less ROS and malondialdehyde (MDA) concentrations were recorded with the addition of appropriate concentrations of ASTA compared to control. In addition, the levels of mitochondrial membrane potential (MMP), adenosine triphosphate (ATP), and lactate dehydrogenase (LDH) in the 1μg/mL ASTA group improved compared to the control group, and decreased the amount of AIF protein level but increased the Bcl-2 protein level (P < 0:05). Collectively, these results demonstrate that adding ASTA in the BPSE promoted rooster freeze-thaw sperm quality, which may be related to reducing ROS levels, protecting the antioxidant defense system, preventing lipid peroxidation, improving mitochondrial structural and functional integrity, and inhibiting sperm apoptosis.

Current summer heat waves impair rainbow trout (Oncorhynchus mykiss) spermatogenesis: Implications for future fish farming management practices in South Europe

Freshwater environments provide different ecosystem services for human well-being, and are one of the most important natural sources of healthy animal protein. Climate change and extreme temperature events, among other factors, represent a growing concern for their sustainable use. In contrast to the research effort to elucidate how global warming affects these aquatic environments, few studies pay attention to the potential effects of heat waves, a current phenomenon with direct effects on contemporaneous organisms. Here, the potential effects of a single heat wave event on rainbow trout (Oncorhynchus mykiss) males, mimicking a recorded environmental event, have been evaluated by means of biometric, redox and stress response, plasma testosterone, histopathology and transcriptomic analyses. Environmental monitoring showed how, during the last 4 years, mean water temperature increased (2–4 °C; from April to October), heat wave duration progressively increased (from 15 to 100 days), and mean intensities ranged 1.7–3.8 °C with a maximum of 8.0 °C. An experimentally recreated heat wave lasting only 16 days, with mean and maximum intensities of 2.7 and 6.7 °C, induced a decrease in body weight and total antioxidant status, but increased blood plasma cortisol levels and redox enzyme activity. The induced heat wave decreased testosterone plasma levels and sperm quality, arrested spermatocyte type I and II differentiation and increased spermatozoa apoptosis. These effects were correlated with a differential expression of 1156 genes (116 up- and 1040 down-regulated genes) in exposed fish when compared to Control fish, reflecting an alteration in cell apoptosis and spermatozoa maturation processes. These results not only increase concern about current heat wave events, recreating a real scenario, but also unveil for the first time the particular molecular mechanisms of subsequent spermatogenesis disruption, opening new avenues for designing urgent and necessary strategies to mitigate the effects of extreme climate change conditions on freshwater aquaculture.

Damage to Mitochondria During the Cryopreservation, Causing ROS Leakage, Leading to Oxidative Stress and Decreased Quality of Ram Sperm.

Semen cryopreservation can achieve long-term preservation of sperm. Ice crystal damage, as well as oxidative stress, result in mitochondrial dysfunction and a reduction in sperm motility after thawing. However, limited information exists regarding the impact of reactive oxygen species (ROS) and mitochondria on the cryopreservation of ram sperm. The primary objective of this study was to investigate the relationship between ROS and mitochondria concerning sperm quality during the cryopreservation of ram sperm. This investigation assessed sperm motility, kinematic characteristics, membrane integrity, acrosome integrity, mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) levels, expression of mitochondrial respiratory genes (NDUFV2, SDHA, CYC1, and COXIV), ROS levels, malondialdehyde (MDA) content, phosphatidylserine externalisation rate, sperm ultrastructure, mtDNA copy number, expression of apoptosis-related genes (Bax, Caspase-3, and Caspase-8), Cytochrome C, and Caspase-3 content. The results showed the cryopreservation significantly (p < 0.05) decreased motility, kinetic parameters, membrane integrity, acrosome integrity, MMP, ATP, mRNA expression levels of mitochondrial respiratory-related genes, and significantly (p < 0.05) increased ROS levels, MDA content, phosphatidylserine externalisation rate, damage of sperm ultrastructure, mtDNA copy number, mRNA expression levels of apoptosis-related genes, Cytochrome C and Caspase-3 content compared to the fresh semen group. In conclusion, the cryopreservation causes damage to mitochondria, leading to increased ROS and subsequent oxidative stress. This process also initiates mitochondrial dysfunction and interferes with the electron transport chain, ultimately resulting in decreased MMP and ATP production. Furthermore, the liberation of Cytochrome C prompted the increase in Caspase-3 expression and subsequent sperm apoptosis occurred, ultimately leading to a deterioration in sperm quality after thawing.

Sulforaphane acts through the NFE2L2/AMPK signaling pathway to protect boar spermatozoa from cryoinjury by activating antioxidant defenses

During cryopreservation, a substantial portion of spermatozoa undergoes apoptosis due to cryoinjury, resulting in decreased fertility. Boar spermatozoa are highly sensitive to temperature, with low temperature triggering reactive oxygen species (ROS) generation, leading to oxidative stress and apoptosis. Sulforaphane (SFN), a potent natural compound found in cruciferous vegetables, is efficacious in mitigating oxidative stress. We here supplemented different SFN concentrations (0, 1.25, 2.5, 5, 10, and 20 μM) into the freezing extender to explore its effect on boar sperm during cryopreservation and determine the optimal SFN concentration. Supplementation of 5 μM SFN exhibited the highest sperm motility, motion performance, plasma membrane integrity, acrosome integrity, and antioxidant properties (total antioxidant capacity (T-AOC) and antioxidant enzyme activity) after freezing and thawing. Then, RT group, C group and C + SFN group were established to explore the effect of SFN on the cryopreservation-induced sperm apoptosis level and fertilizing capacity of post-thawed sperms. SFN effectively rescued the apoptosis and fertilizing capacity of post-thawed sperms. Mechanistically, SFN activated the redox-sensitive nuclear factor erythroid 2-related factor 2 (NRF2/NFE2L2) by promoting adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. This activation improved antioxidant defenses, ultimately improving cryoinjury in boar spermatozoa. In summary, SFN suppressed cryopreservation-induced apoptosis of spermatozoa by activating antioxidant defenses and the AMPK/NFE2L2 signaling pathway. These findings suggest a novel approach for augmenting the cryoprotective efficiency and spermatozoa fertility after cryopreservation.

Predicting Boar Sperm Survival during Liquid Storage Using Vibrational Spectroscopic Techniques.

Artificial insemination (AI) plays a critical role in livestock reproduction, with semen quality being essential. In swine, AI primarily uses cool-stored semen adhering to industry standards assessed through routine analysis, yet fertility inconsistencies highlight the need for enhanced semen evaluation. Over 10-day storage at 17 °C, boar semen samples were analyzed for motility, morphology, sperm membrane integrity, apoptosis, and oxidative stress indicators. Additionally, machine learning tools were employed to explore the potential of Raman and near-infrared (NIR) spectroscopy in enhancing semen sample evaluation. Sperm motility and morphology gradually decreased during storage, with distinct groups categorized as "Good" or "Poor" survival semen according to motility on Day 7 of storage. Initially similar on Day 0 of semen collection, "Poor" samples revealed significantly lower total motility (21.69 ± 4.64% vs. 80.19 ± 1.42%), progressive motility (4.74 ± 1.71% vs. 39.73 ± 2.57%), and normal morphology (66.43 ± 2.60% vs. 87.91 ± 1.92%) than their "Good" counterparts by Day 7, using a computer-assisted sperm analyzer. Furthermore, "Poor" samples had higher levels of apoptotic cells, membrane damage, and intracellular reactive oxygen species on Day 0. Conversely, "Good" samples maintained higher total antioxidant capacity. Raman spectroscopy outperformed NIR, providing distinctive spectral profiles aligned with semen biochemical changes and enabling the prediction of semen survival during storage. Overall, the spectral profiles coupled with machine learning tools might assist in enhancing semen evaluation and prognosis.

Environmental arsenic exposure and reproductive system toxicity in male and female and mitigatory strategies: a review.

Environmental Arsenic (As) exposure is one of the main health challenges in different area of the world. As is a significant factor responsible to the reproductive system toxicity in both male and female. In this study, the most important effects mechanisms and biomarkers related to environmental exposure to As and the reproductive system toxicity, and infertility risk are reviewed in male and female. The results showed that the most important As-induced reproductive system toxicity in the male were alteration in the quantity and quality of semen, testicular toxicity, oxidative stress, testosterone reduction, and sperm apoptosis. For female were oxidative stress, spontaneous miscarriage, reproductive cycle disruption, decrease in the estradiol, progesterone, and testosterone levels and impair fecundity. The main mechanisms of reproductive system toxicity caused by As exposure in male were, genotoxic effects, reduction of glutathione, disruption of sex hormones, sperm flagellum formation impairment, inhibition of spermatogenesis, disruption of cell signaling pathways, and metabolites disruption. For female were abnormal signaling in gene expression, hormonal homeostasis, As-accumulation in placental tissue and creation of reactive oxygen, disruption in the neurotransmitters balance, and sex hormones disruption. The suitable biomarkers for As-induced reproductive toxicity in male were changes in testosterone, one-carbon and lipid metabolism, noncoding RNAs, and steroid hormone homeostasis, and for female was human chorionic gonadotropin (hCG) changes. Finaly, taking selenium, zinc, silymarin, vitamins (C and E) and phytonutrients can be effective in reducing the As-induced reproductive system toxicity and infertility risk.

Integrated sperm movement, proteomics, and phosphoproteomics elucidate the roles of osmolality, ions, and key proteins in sperm activation of Nile tilapia (Oreochromis niloticus)

Nile tilapia (Oreochromis niloticus) is an important aquaculture fish around the world and has a wide range of tolerance to salinity, providing great economic value in aquaculture industry and showing an excellent ecological adaptation. However, the best sperm activation condition and sperm activation mechanism of this euryhaline fish remains unclear. In this study, we applied the sperm movement analysis, proteomics, and phosphoproteomics to explore the effects of osmolality and ions and to reveal sperm activation mechanism of Nile tilapia. Our results showed that low osmolality contributed to sperm activation compared with high osmolality. Adding Na+ and Ca2+ enhanced sperm motility after sperm activation. Under 100 mOsm·kg−1, adding 44 mM Na+ and 4 mM Ca2+ was a successful protocol for sperm activation. Proteomics and phosphoproteomics analyses identified 677 differentially expressed proteins and 245 differentially expressed phosphorylated proteins, respectively, among which 21 proteins and 11 phosphorylated proteins as key molecules were involved in Ca2+ mediated signal transduction, glucose metabolism, lipid metabolism, and apoptotic cell death. Key protein ORAI1 promoted extracellular Ca2+ influx to activate Ca2+ mediated signal transduction. Converting glycogenolysis and glycolysis to pyruvate metabolism and fatty acid β-oxidation was a critical energy metabolic adaptation mechanism. The Hsp90 was a critical sperm activation biomarker in loosing of sperm motility and apoptosis. A putative proteomic and phosphoproteomic response network was constructed to reveal the sperm activation mechanism of Nile tilapia. Our study provides a new insight into sperm activation mechanism of this euryhaline fish and facilitates future application of best activation protocol to the fertilization and breeding of Nile tilapia.

Dietary alpha-linolenic acid supplementation enhances semen quality, antioxidant capacity, and sperm survival in aging breeder roosters

Aging in breeder roosters is often accompanied by a decline in semen quality, negatively impacting reproductive performance. This study aimed to investigate the effect of dietary alpha-linolenic acid (ALA), an essential omega-3 polyunsaturated fatty acid, on semen quality, antioxidant capacity, and sperm survival in aging breeder roosters. Roosters were divided into 4 groups and fed diets supplemented with 0%, 0.5%, 1%, and 2% ALA for 6 wk. Results indicated significant improvements in semen volume, sperm viability, and sperm density in ALA-supplemented groups compared to the control (P < 0.05). The 1% ALA group exhibited the most notable enhancements in sperm viability and density. Additionally, ALA supplementation increased the activities of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and reduced malondialdehyde (MDA) levels, indicating enhanced antioxidant capacity (P < 0.05). Furthermore, ALA improved mitochondrial membrane potential (MMP) and reduced early and late sperm apoptosis, with the 2% ALA group showing the highest MMP and the lowest ROS-positive rate (P < 0.05). These findings suggest that dietary ALA supplementation enhances semen quality and antioxidant defenses, and mitigates oxidative stress, thus supporting the reproductive health of aging breeder roosters. This study underscores the potential of ALA as a dietary strategy to improve reproductive efficiency in poultry production.

Semen Parameters Can Be Used As A Credible Marker with Doppler Ultrasonography in the Diagnosis of Subclinical Varicocele Cases

OBJECTIVES: The link between varicoceles and male infertility has been a problem of debate for more than half a century. A substantial amount of data about varicocelectomies’ effects has been provided, but inadequate study designs and heterogeneity of current studies make these data rarely conclusive. This article investigates whether semen and sperm analysis in subclinical varicocele patients without any clinical signs diagnosed by Doppler Ultrasonography (USG) can be used as a diagnostic tool. STUDY DESIGN: The current prospective study included infertile male patients (n=44) enrolled in the Urology Clinic of Biruni University Hospital from January 2017 to January 2018. Patients were divided into two groups: 1st group as the control group (CG) (n=22): No varicocele as determined by Doppler USG, and 2nd group as the test group (TG) (n=22): Subclinical varicocele (SCV) as determined by Doppler USG. A semen analysis was done. Sperm were dyed with aniline blue and chromomycin A3 (CMA3), acridine orange (AO), propidium iodide (PI), and Rhodamine 123 (Rh123) for the determination of sperm maturation, sperm DNA fragmentation, apoptosis, and sperm mitochondrial membrane potential, respectively. Student-t Test was used for statistical analysis. p&lt;0.05 was considered significant. RESULTS: The sperm concentration of the CG was higher than the TG (p=0.98, p&gt;0.05). Forward sperm motility in the CG was higher than in the TG (p&lt;0.001, p&lt;0.05). Sperm with normal morphology in the TG was lower than in the CG (p&lt;0.001, p&lt;0.05). Sperm neck anomalies were higher in varicocele cases (p&lt;0.001, p&lt;0.05). Sperm maturation at the TG was lower than the CG (p&lt;0.001, p&lt;0.05). A high apoptotic sperm rate was found at the TG (p&lt;0.001, p&lt;0.05). Sperm mitochondria potential at the TG was lower than the CG (p&lt;0.001, p&lt;0.05). Sperm chromatin condensation at the TG was higher than the CG (p&lt;0.001, p&lt;0.05). CONCLUSIONS: The analysis of sperm DNA and apoptosis in SCV cases can be used as a reliable diagnostic tool to confirm Doppler USG.

External pressure induces the dysfunction of spermatogonia via triggering the intrinsic pathway of apoptosis.

Cryptorchidism, the failure of testes to descend into the scrotum, exposes the testes to higher temperature and external pressure. Scholars from Razi University found through research conducted at different pressure gradients (0, 25, 50, and 100 mmHg) and time gradients (2 and 4 h) that high hydrostatic pressure may lead to sperm apoptosis. In this work, we investigated the effect of external pressure on spermatogonia, exploring a new mechanism of male infertility caused by cryptorchidism. Various pressure gradients (0, 25, 50, and 100 mmHg) were applied to spermatogonia for different durations (0, 2, and 4 h) in the Cell Counting Kit-8 (CCK8) experiment. Morphological changes, cell ultrastructure, apoptosis rates, and the expression of apoptosis-related proteins (bax, bcl-2, caspase-3, and caspase-9) were assessed through immunofluorescence, electron microscopy, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, flow cytometry, immunohistochemistry, real-time quantitative polymerase chain reaction (qPCR), and western blot. The cell viability assay showed that higher external pressure had a greater negative time-dependent impact on cell viability. Immunofluorescence results indicated that external pressure stimuli altered the morphology of spermatogonia. The results of TUNEL assay and flow cytometry demonstrated that external pressure stimuli induced apoptosis in spermatogonia. Transmission electron microscopy (TEM) observations showed the generation of apoptotic bodies, mitochondrial swelling, vacuolization, and mitochondrial cristae fusion. The results of immunohistochemistry indicated that pressure induced the expression of caspase-3 and caspase-9 proteins. qPCR and western blot analyses revealed an increased ratio of bax/bcl-2 and expression of caspase-3 and caspase-9. Methazolamide (cytochrome C inhibitor) blocked the pressure-induced cell apoptosis and inhibited the activation of caspase-3 while Z-IETD-FMK (caspase-8 inhibitor) did not. External pressure promotes spermatogonia apoptosis through the intrinsic apoptosis pathway, which may be one of the mechanisms of male infertility induced by cryptorchidism.

Decreased human sperm motility and vitality after fast gravity load changes in a parabolic flight

Little is known about the effects of low gravity on human gametes. The aim of this study was to analyze if fresh human sperm samples after fast gravity load changes suffered any detrimental effect in comparison to the splits maintained in Earth's gravity. Fifteen fresh samples from normozoospermic donors were analyzed. Statistically significant differences in vitality (69.7 ± 9.9 % vs 72.4 ± 9.7 %, [95 % CI: 0.002,0.07]); motile sperm concentration (23.7 ± 15.3 M/ml vs 31.5 ± 25.1 M/ml, [95 % CI: 1.03,14.65]); grade “a” sperm concentration (8.7 ± 6.5 M/ml vs 11.7 ± 9.9 M/ml, [95 % CI: 0.71,5.28]); percentage of progressive motility sperm (30 ± 12.9 % vs 36 ± 14.3 %, [95 % CI: 0.10,0.37]) and curvilinear velocity VCL: 45.7 ± 12.8 μm/s vs 47.7 ± 13.3 μm/s, [95 % CI: 0.79,3.22]) were observed. No statistical differences were observed in other sperm kinematic parameters, morphology, DNA fragmentation, apoptosis, and oxidative stress. In conclusion, even though it did not result in a total loss, heavy gravity load changes including microgravity causes a significant decrease in sperm vitality and motility suggesting that negative consequences would be even higher if the exposure were longer. The results obtained indicate that further research is really needed before Assisted Reproduction will be considered for the future human reproduction outside the Earth.

Carboxyfullerene C60 preserves porcine sperm by enhancing antioxidant capacity and inhibiting apoptosis and harmful bacteria.

This study used a porcine model to systematically investigate whether carboxyfullerene C60(CF-C60) can be used for sperm preservation. The results indicated that CF-C60 supplementation can preserve porcine sperm quality during storage at 17°C. This effect was attributable to an improvement in the antioxidant capacity of sperm through a decrease in the reactive oxygen species (ROS) level. Additionally, CF-C60 can maintain mitochondrial function, inhibit sperm apoptosis through the ROS/Cytochrome C (Cyt C)/Caspase 3 signaling pathway, and mediate suppression of bacterial growth through the effects of ROS. Finally, the results of artificial insemination experiments indicated that insemination with CF-C60-treated sperm can increase the total number of offspring born and reduce the number of deformed piglets. Thus, CF-C60 is safe for use as a component of semen diluent for sperm storage.

P-044 Increased CYP1A1 expression enhances sperm apoptosis in idiopathic infertile men

Abstract Study question How are the CYP1A1 and Caspase-9 genes expression and the relationship among the expression of these genes with sperm parameters in idiopathic infertile men? Summary answer The CYP1A1 and Caspase-9 gene expression showed a significant increase in patients in comparison with the healthy group. What is known already CYP1A1 (Cytochrome P450 Family 1 Subfamily A Member 1) plays a crucial role in xenobiotic metabolism induced by aryl hydrocarbon receptor (AHR). AHR, as a ligand-activated transcription factor is involved in exogenous ligand activation. CYP1A1 is one of the most essential enzymes in phase 1 of detoxification, metabolism, and bio-activation of carcinogens and is the most well-known target gene for AHR. Monooxygenase activity of CYP1A1 may lead to oxidative stress and the formation of reactive intermediates with destructive effects such as apoptosis in testicular germ cells. CYP1A1 may lead to apoptosis via Caspase-9 activation. Study design, size, duration In this study, we aimed to determine the CYP1A1 and Caspase-9 gene expression. Participants/materials, setting, methods The infertile idiopathic and healthy fertile men were selected and evaluated for sperm analysis and gene expression. The expression levels of CYP1A1 and Caspase-9 were also determined by real time PCR. Main results and the role of chance The sperm count, morphology and motility were significantly lower in patients compared to the control group (p &amp;lt; 0.05). The CYP1A1 and Caspase-9 gene expression showed a significant increase in patients in comparison with the healthy group (p &amp;lt; 0.05). Limitations, reasons for caution Further investigations of the effect of CYP1A1 and Caspase-9 expressions on infertility by using more infertile patients and also studying the effect of other important genes such as AHR can show us more accurate results. Wider implications of the findings Our results suggest that increased CYP1A1 and Caspase-9 expression could increase the rate of male infertility. In addition, the increase in Caspase-9 expression could lead to a reduced number of sperms and an increased infertility rate by increased apoptosis in the spermatogenic lineage. Trial registration number not applicable

The Effects of Supplementation of the Freezing Extender with Silymarin on the Quality Parameters of Frozen-Thawed Arabian Stallion Sperm: A Preliminary Evaluation.

This study evaluated the effects of supplementation of the freezing extender with different concentrations of silymarin on the quality of frozen-thawed Arabian stallion spermatozoa. Semen samples from three stallions (1, 2, and 3) were suspended in the freezing extender without or with silymarin (0, 25 μg/mL, 50 μg/mL, 75 μg/mL, and 100 μg/mL) and cryopreserved in 0.5 mL straws. After 1 month of storage, the frozen semen samples in straws were thawed and evaluated in terms of viability, mitochondrial membrane potential, kinematic parameters, total and progressive motility, plasma membrane integrity, lipid peroxidation, and DNA fragmentation. The findings indicated that 25-100 μg/mL of silymarin significantly improved viability and mitochondrial membrane potential while reducing the stallion sperm lipid peroxidation, DNA fragmentation, and apoptosis compared with the control group (p < 0.05). Silymarin concentrations of 75 μg/mL and 100 μg/mL significantly increased progressive motility and plasma membrane integrity (p < 0.05). Based on our findings, it can be inferred that silymarin exhibited a dose-dependent enhancement in the frozen-thawed Arabian stallion sperm quality. The most favorable outcomes were observed when 100 μg/mL silymarin was used.

Effect of interleukin 6 (IL-6) on sperm quality, kinematic parameters, acrosome integrity, apoptosis, ultrastructure, and molecular docking in cryopreserved ram spermatozoa

Sperm cryopreservation can lead to subfertility due to potential damage to sperm DNA, membranes, and overall motility caused by the freeze-thaw process. Interleukin-6 (IL-6) is a versatile cytokine with various roles in reproductive processes. However, the impacts of IL-6 supplementation on cryopreserved ram sperm have not been thoroughly investigated. Therefore, this study aims to assess the influence of IL-6 on the sperm quality of cryopreserved ram sperm. Ram semen was collected, pooled, and extended with tris-citrate soybean lecithin extender supplemented with 0, 50, 100, and 200 ng/mL of IL-6. The samples experienced a standard freezing protocol, and sperm quality, kinematic parameters, ultrastructure, and molecular docking of cryopreserved ram spermatozoa were evaluated. The results showed that sperm kinematics, viability, progressive motility, and membrane integrity were significantly enhanced by the addition of 100 or 200 ng of IL-6/mL (p < 0.05). Semen supplemented with 100 or 200 ng/mL of IL-6 also exhibited higher percentages of sperm kinematics, including DAP, DCL, DSL, VSL, VAP, VCL, and ALH, compared to other groups (p < 0.05). IL-6 supplementation enhanced acrosome integrity, and reduced caspase-3 activity in post-thawed ram spermatozoa (p < 0.05) compared to untreated group. Supplementation with IL-6 (200 ng/mL) significantly decreased oxidative biomarkers (NO, MDA, and H2O2) (p < 0.001) and improved total antioxidant capacity (p < 0.05). The percentage of sperm damage (tail, head, and midpiece) was significantly reduced by IL-6 supplementation (p < 0.05). Electron micrographs showed that supplementation with 100 or 200 ng/mL IL-6 protected acrosome stability, plasma membrane integrity, and sustained the ultrastructure integrity of cryopreserved ram spermatozoa. The docking exploration indicates a higher binding affinity with sperm function biomarkers, including caspase 3, BCL2, and PSMA6, with binding energies of − 52.30 kcal/mol, − 56.04 kcal/mol, and − 57.06 kcal/mol, respectively. In conclusion, the addition of IL-6 to the freezing extender can enhance the post-thaw quality of cryopreserved ram spermatozoa.

The neonicotinoid, imidacloprid, disrupt the chicken sperm quality through calcium efflux

Imidacloprid (IMI), an insecticide from the neonicotinoid group widely used in agriculture, has drawn attention due to its potential harmful effects on non-target species, including bird populations. In the present work, we investigated the effect of IMI on avian semen by in vitro exposure of rooster spermatozoa to this pesticide. The semen was collected twice a week. Samples collected on one day were pooled and incubated with the following IMI concentrations: 0 mM, 0.5 mM, 5 mM, 10 mM, and 50 mM at 36°C for 3 h. Comprehensive semen analysis was carried out after 1 h and 3 h of incubation, evaluating sperm motility parameters with the CASA system and using flow cytometry to assess membrane integrity, mitochondrial activity, acrosome integrity, chromatin structure, intracellular calcium level and apoptosis markers such as: early apoptosis and caspase activation and lipid peroxidation. The results of the first experiment suggest that low concentrations of IMI have a different effect on sperm motility compared to higher concentrations. In IMI samples, we also observed a lower percentage of cells with a high level of calcium ions compared to the control, and a lower level of lipid peroxidation. We concluded that IMI may act as a blocker of calcium channels, preventing the influx of these ions into the cell. To confirm this mechanism, we conducted a second experiment with calcium channel blockers: SNX 325, MRS-1845, and Nifedipine. The results of this experiment confirmed that the mechanism of action of IMI largely relies on the blockade of calcium channels in rooster sperm. Blocking the influx of calcium ions into the cell prevents the formation of Ca²⁺-dependent pores, thereby preventing an increase in cell membrane permeability, ultimately blocking early apoptosis and lipid peroxidation in chicken spermatozoa.

Star1 gene mutation reveals the essentiality of 11-ketotestosterone and glucocorticoids for male fertility in Nile Tilapia (Oreochromis niloticus)

Steroidogenic acute regulatory protein (Star) plays an essential role in the biosynthesis of corticosteroids and sex steroids by mediating the transport of cholesterol from the outer to the inner membrane of mitochondria. Two duplicated Star genes, namely star1 and star2, have been identified in non-mammalian vertebrates. To investigate the roles of star genes in fish steriodogenesis, we generated two mutation lines of star1−/− and star1−/−/star2−/− in Nile tilapia (Oreochromis niloticus). Previous studies revealed that deficiency of star2 gene caused delayed spermatogenesis, sperm apoptosis and sterility in male tilapia. Our present data revealed that mutation of star genes impaired male fertility. Disordered seminiferous lobules and spermatic duct obstruction were found in the testis of both types of mutants. Moreover, significant decline in semen volume, sperm abnormality and impaired fertility were also detected in star1−/− and star1−/−/star2−/− males. In star1−/− male fish, lipid accumulation, up-regulation of steroidogenic enzymes, and significant decline of androgens were found. Additionally, hyperplasic interrenal cells, elevated steroidogenic gene expression level and decline of serum glucocorticoids were detected in star1 mutants. Intriguingly, either 11-KT or cortisol supplementation successfully rescued the impaired fertility of the star1−/− mutants. Taken together, these results further indicate that Star1 might play critical roles in the production of both 11-KT and glucocorticoids, which are indispensable for the maintenance of male fertility in fish.

Tert-Butylhydroquinone Mitigates T-2-Toxin-Induced Testicular Dysfunction by Targeting Oxidative Stress, Inflammation, and Apoptosis in Rats.

Tert-butylhydroquinone (tBHQ) has emerged as a promising candidate for mitigating the adverse effects of T-2-induced reproductive toxicity. The protective effects of tBHQ on rat sperm quality, testicular injury, apoptosis, and inflammation induced by T-2 toxin exposure were investigated. Histopathological examination of testicular tissues revealed severe damage in the T-2-treated group, characterized by disorganized germ cell arrangement, thinning of the convoluted seminiferous tubule walls, and significant cellular necrosis. However, tBHQ administration, either as a preventive or therapeutic measure, mitigated this structural damage. Image analysis confirmed an increase in the cross-sectional area and height of the convoluted seminiferous tubules in the tBHQ-treated groups compared to the T-2-treated group (p < 0.05), indicating tBHQ's efficacy in alleviating testicular damage. Additionally, tBHQ treatment significantly inhibited T-2-induced apoptosis of testicular tissue cells, as evidenced by the results showing reduced apoptotic cell counts and downregulation of the BAX/BCL2 ratio and caspase-3 expression (p < 0.05). tBHQ significantly increased the concentrations of the antioxidant factors SOD, CAT, TAC, and GSH-PX. Furthermore, tBHQ attenuated the inflammatory response induced by T-2 exposure, as indicated by the decreased mRNA expression of the proinflammatory cytokines Tnf, Il1, and Il10 in testicular tissue (p < 0.05). Additionally, tBHQ treatment alleviated the decline in serum testosterone induced by the T-2 and promoted testosterone synthesis gene expression, including for the genes 17β-HSD and Cyp11a1, in rat testes (p < 0.05). These findings underscore tBHQ's role as a therapeutic agent combatting T-2-induced reproductive toxicity, highlighting its antioxidative, anti-apoptotic, and anti-inflammatory properties. Further elucidation of tBHQ's mechanisms of action may offer novel strategies for preventing and treating reproductive disorders induced by environmental toxins.

Protective effects of canthaxanthin-loaded seminal exosomes on the quality of human spermatozoa during cryopreservation

Sperm cryopreservation is a common strategy for preserving male fertility; however, it may cause detrimental alterations in the structure and biological role of spermatozoa. The objective of this study is to mitigate the damages caused by cryopreservation through the use of canthaxanthin-loaded seminal exosomes (CAN-loaded EXO). To achieve this, Exosomes were isolated from the human seminal fluid through serial ultracentrifugation and characterized using different methods. Canthaxanthin was loaded into exosomes using the sonication method and incubated with spermatozoa for 1 h. Then the semen was mixed with CryoSperm medium and transferred into straws. The straws were initially placed in nitrogen vapor and then submerged in liquid nitrogen. After one month, the samples were thawed, and sperm parameters, lipid peroxidation, total antioxidant capacity (TAC), reactive oxygen species (ROS) levels, sperm DNA fragmentation (SDF), and sperm apoptosis were assessed. The results demonstrated the successful isolation of exosomes with a spherical morphology, a particle size of 104.5 nm, and a zeta potential of −12.32 mV. Canthaxanthin was loaded into exosomes with an encapsulation efficiency of 63.7 %. Motility and vitality of spermatozoa were improved in the presence of CAN-loaded EXO compared to the control group (p < 0.05). Incubation of spermatozoa with CAN-loaded EXO enhanced TAC levels and decreased ROS levels, lipid peroxidation, SDF, and apoptosis compared to the control group (p < 0.05). However, CAN-loaded EXO had no significant effect on the morphology of spermatozoa. These findings suggest that exosomes have the potential to serve as a novel drug delivery platform for protecting spermatozoa from cryodamage while enhancing the bioavailability of antioxidants.

Oxidative stress on alpaca epididimal sperm frozen with different concentrations of seminal plasma

Objective. To assess the oxidative stress on alpaca epididimal sperm frozen with different concentration of seminal plasma. Materials and methods. 29 post mortem alpaca epididymis were used. Epididymal sperm were obteined thought cuts and suspended in a diluent based on skim milk, egg yolk and fructose and dimethylacetamine. Samples were separated into four aliquots which were supplied with seminal plasma (v/v) in concentrations of 0, 10, 25 and 50% respectively; then, sperm motility was assessed before freezing; then, motility was assessed before freezing with an automatic freezer machine. After thawing, mitochondrial membrane activity, sperm viability, lipid peroxidation and sperm apoptosis were assessed using flow cytometry with images. Results. Sperm exposed to 50% seminal plasma showed the lowest post-thaw motility (3.5±3.7%) and the highest percentages of apoptotic cells (71.43±20.6%). No significant differences were found in the rest of parameters. Conclusions. This study constitutes non-conclusive evidence that presence of seminal plasma does not affect viability, mitochondrial activity, or lipid peroxidation of alpaca epididymal sperm during cryopreservation processes; however, when it is absent or added up to 25% in the cryopreservation process, it may be possible to obtain better results in terms of sperm motility and sperm apoptosis.