Reactive oxygen species and sperm cells

Flavone and 3-hydroxyflavone supplementation in cryopreservation medium protects canine sperm against apoptosis and lipid peroxidation

Cryopreservation is a pivotal technique in safeguarding genetic material across diverse species, despite its inherent challenges linked to induced spermatozoa damage, notably apoptosis and lipid peroxidation (LPO). Given the insufficient antioxidant defense of spermatozoa against LPO, there is a rising interest in integrating additional additives into extenders to ameliorate mammalian semen quality. Among these additives, flavonoids have garnered considerable attention due to their potent antioxidative properties. Hence, our study aimed to assess the efficacy of flavone (FL) and 3-hydroxyflavone (3-OH = ) supplementation in the cryopreservation medium to protect canine sperm against the damaging impacts of freezing and ensure the preservation of their reproductive potential. Semen was collected from five Beagle stud dogs and then pooled. Then, the sample was divided into 7 groups, each treated with 1) 0 mM, 2) 0.1 mM FL, 3) 0.2 mM FL, 4) 0.4 mM FL, 5) 0.1 mM 3-OH = , 6) 0.2 mM 3-OH = , 7) 0.4 mM 3-OH = . Semen samples were subjected to cryopreservation in French straws and glycerol as a cryoprotectant. In the frozen thawed semen, sperm motility parameters by CASA system and sperm membrane integrity, acrosome status, mitochondrial activity, DNA fragmentation, early apoptosis with capacitation, and LPO were assessed using flow cytometry just after thawing (0 h) and 4 h post thaw. Results reveal significant increase in the proportion of live spermatozoa with undamaged acrosomes in the FL 0.1 and 3-OH = 0.2 groups at 0 h post thaw. At this time point, 3-OH = 0.1 significantly reduced the DNA fragmentation index (DFI) compared to the FL 0.1 and 0.2 groups. However, after the next 4 h, 3-OH = 0.4 exhibited the lowest (P < 0.05) DFI compared to FL 0.2 and 3-OH = 0.1. Additionally, 3-OH = 0.4 showed the highest (P < 0.05) proportion of non apoptotic and non capacitated spermatozoa compared to FL 0.1 0 h post-thaw. Simultaneously, the same group demonstrated significant reduction in apoptotic and capacitated sperm cells, at 0 h and 4 h post-thaw. Moreover, 3-OH = at 0.1 (0 h and 4 h) and 0.2 mM (4 h) significantly enhances the proportion of live sperm without LPO post thaw. Whitin the FL groups, only 0.4 FL significantly increased the percentage of live sperm without LPO. No significant effect of the tested substances was observed on sperm motility, cell membrane integrity, or mitochondrial activity. These findings highlight the promising role of flavone and 3-hydroxyflavone in enhancing sperm resilience during cryopreservation, suggesting their protective function against acrosome damages, capacitation, apoptosis and lipid peroxidation.

Application of antioxidants in extender on bull sperm cryopreservation to reduce the male effect in dairy fertility

Because male and female effects on fertility must be considered, it may be difficult to achieve accurate and repeatable fertility predictions using only sperm characteristics given differences in breed, health, and season. Improving sperm quality after cryopreservation may be a method to reduce the male effect on the fertility outcome. This study was conducted using 2 different Certified Semen Service approved extenders, one containing plant-derived antioxidants, to assess cryopreserved sperm quality and determine pregnancy per artificial insemination (P/AI) in a commercial dairy farm. Beef bull ejaculates (n = 24 ejaculates, n = 4 bulls) were split and frozen in egg-yolk-TRIS (EYT) or GameteGuard-FB cryopreservation extenders. Frozen-thawed sperm was evaluated for sperm quality and used for insemination in dairy cows (n = 4856). There was an improvement in total and progressive motility, acrosome integrity, and reduction of DNA fragmentation at 0 and 3 h after thawing in sperm frozen in GameteGuard-FB when compared with the EYT extender. An overall 12.7% improvement in pregnancy per AI (P/AI) was observed when GameteGuard-FB (40.8%) was used for cryopreservation when compared with EYT (36.2%). More importantly, GameteGuard-FB frozen semen increased P/AI for first service by 19.5% (35.9% EYT and 42.9% GameteGuard-FB) and 45.0% was also observed at third service (31.3% EYT and 45.4% GameteGuard-FB). The use of GameteGuard-FB resulted in an average 40% P/AI among bulls. Taken together, the increase in cryopreserved sperm quality using GameteGuard-FB can be used to minimize the male effects on pregnancy outcomes in commercial dairy farms.

Structure and Composition of Spermatozoa Fibrous Sheath in Diverse Groups of Metazoa

The proper functioning and assembly of the sperm flagella structures contribute significantly to spermatozoa motility and overall male fertility. However, the fine mechanisms of assembly steps are poorly studied due to the high diversity of cell types, low solubility of the corresponding protein structures, and high tissue and cell specificity. One of the open questions for investigation is the attachment of longitudinal columns to the doublets 3 and 8 of axonemal microtubules through the outer dense fibers. A number of mutations affecting the assembly of flagella in model organisms are known. Additionally, evolutionary genomics data and comparative analysis of flagella morphology are available for a set of non-model species. This review is devoted to the analysis of diverse ultrastructures of sperm flagellum of Metazoa combined with an overview of the evolutionary distribution and function of the mammalian fibrous sheath proteins.

Ameliorative potentials of diosmin and hesperidin fractions on chlorpyriphos-induced changes in reproductive hormones, sperm characteristics, and testicular glycogen in male Wistar rats

Reproductive deficiency is a major outcome of pesticide exposure sequel to cellular oxidative damage to sex organs. Flavonoid possess potent antioxidant capacities to mitigate pesticide related cellular injury. The present investigation examined the mitigative effect of micronized purified fractions of diosmin and hesperidin on reproductive hormones, sperm parameters, and testicular glycogen in male Wistar rats after sub-chronic Chlorpyriphos (CPF) exposure. Twenty-five male Wistar rats (120-145 g) were randomly allocated five rats per group. Group I (DW) received distilled water (2 ml/kg), Group II (S/oil) received soya oil (2 ml/kg), Group III (DAF) received Daflon at 1000 mg/kg, Group IV (CPF) received Chlorpyriphos (7.74 mg/kg), and Group V (DAF + CPF) received Daflon (1000 mg/kg) followed by CPF (7.74 mg/kg) after 30 min of Daflon. This regimen was administered daily for 60 days. After cervical venesection under light chloroform anesthesia, blood samples were examined for levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone. Each rat's testicular tissue was quickly cut, collected, and glycogen evaluated. Sperm concentration, motility, morphology, and viability were measured in the right caudal epididymis. Results revealed that the untreated CPF group had significantly lower FSH, LH, testosterone, testicular glycogen, and sperm concentration. Additionally, CPF group sperm characteristics were abnormal compared to other groups. These reproductive hormones, testicular glycogen, and sperm parameters improved in the Daflon-treated groups. Hence, pre-treatment with flavonoid fractions of diosmin and hesperidin mitigated CPF-induced reproductive toxicity.

A review of recent developments in the application of nanostructures for sperm cryopreservation

In the 1970s, sperm cryopreservation was presented as a unique route to fertility preservation. The ability to cryopreserve sperm from all species is challenging. The sperm cryopreservation process encompasses various cellular stresses such as increased osmotic pressure, ice crystal formation, and thermal shock, therefore decreasing the quality of sperm. The nanostructures due to their inherent features such as reactivity, high uptake, active surface area, and antioxidant activity, have contributed to modifying freezing protocols. In this review, the current state of the art with regards to emerging applications of nanotechnology in sperm cryopreservation are reviewed, some of the most promising advances are summarized, and the limitations and advantages are comprehensively discussed.

DNA Aptamer Raised against Advanced Glycation End Products Improves Sperm Concentration, Motility, and Viability by Suppressing Receptors for Advanced Glycation End Product-Induced Oxidative Stress and Inflammation in the Testes of Diabetic Mice

Type 2 diabetes mellitus (T2DM) is a risk factor for male infertility, but the underlying molecular mechanisms remain unclear. Advanced glycation end products (AGEs) are pathogenic molecules for diabetic vascular complications. Here, we investigated the effects of the DNA aptamer raised against AGEs (AGE-Apt) on testicular and sperm abnormalities in a T2DM mouse model. KK-Ay (DM) and wild-type (non-DM) 4- and 7-week-old male mice were sacrificed to collect the testes and spermatozoa for immunofluorescence, RT-PCR, and histological analyses. DM and non-DM 7-week-old mice were subcutaneously infused with the AGE-Apt or control-aptamer for 6 weeks and were then sacrificed. Plasma glucose, testicular AGEs, and Rage gene expression in 4-week-old DM mice and plasma glucose, testicular AGEs, oxidative stress, and pro-inflammatory gene expressions in 7-week-old DM mice were higher than those in age-matched non-DM mice, the latter of which was associated with seminiferous tubular dilation. AGE-Apt did not affect glycemic parameters, but it inhibited seminiferous tubular dilation, reduced the number of testicular macrophages and apoptotic cells, and restored the decrease in sperm concentration, motility, and viability of 13-week-old DM mice. Our findings suggest that AGEs-Apt may improve sperm abnormality by suppressing AGE-RAGE-induced oxidative stress and inflammation in the testes of DM mice.

Advancements in Understanding and Enhancing Antioxidant-Mediated Sperm Cryopreservation in Small Ruminants: Challenges and Perspectives

Cryopreservation poses significant challenges to the preservation of sperm integrity and function, particularly in small ruminants where cryodamage is pronounced. This review explores the molecular mechanisms underlying sperm cryodamage and strategies for improving cryopreservation outcomes, with a focus on the role of antioxidants. Cryopreservation-induced alterations in proteins and RNA transcripts critical for sperm function, including motility, capacitation, fertilization, and embryo development, are discussed. Proteomic, transcriptomic, and epigenomic advancements have provided valuable insights into these mechanisms, offering potential biomarkers for predicting sperm freezability and enhancing cryopreservation strategies. Combining technologies such as mass spectrometry and flow cytometry allows for a comprehensive understanding of molecular and cellular changes induced by the freezing-thawing process. However, challenges remain in optimizing cryoprotectant formulations and antioxidant supplementation to improve post-thaw sperm fertility. Further research is needed to explore a wider range of novel cryoprotectants, antioxidants, and proteins for cryopreservation media, as well as to validate their efficacy in enhancing sperm viability and function. Additionally, investigations into the effects of cryopreservation on RNA transcripts and epigenetic factors in small ruminant species are warranted to advance our understanding of sperm preservation. Overall, this review highlights the importance of antioxidants in mitigating cryodamage and underscores the need for continued research to refine cryopreservation protocols and improve reproductive outcomes in small ruminants.

Boar semen cryopreservation: State of the art, and international trade vision

Biosecurity is a major concern in the global pig production. The separation in time of semen collection, processing and insemination in the pig farm is a few days for chilled semen but it can be indefinite when using cryopreserved semen. Field fertility results of boar cryopreserved semen are close to chilled semen, which makes it a valuable resource for the establishment of semen genebanks, long-distance semen trade, and the implementation of other technologies such as the sex-sorted semen. But cryopreserved semen is far from being routine in pig farms. The most recent research efforts to facilitate its implementation include the use of additives before freezing, or in the thawing extender. Long-term preserved semen trade is a biosecurity challenge. To harmonize international trade of germplasm, the World Organization of Animal Health (WOAH) established a regulatory framework for all member countries. The present paper aims to review the latest advances of boar semen cryopreservation with special focus on the benefits of its inclusion as a routine tool in the pig industry. We also review recently reported field fertility results of cryopreserved semen, its international trade compared to chilled semen, and the regulatory framework involved. Boar cryopreserved semen is a valuable tool to control biosecurity risk, implement other technologies, and facilitate international trade. Research already demonstrated good field fertility results, but it still represents less than 0.1 % of the international trade. As boar cryopreserved semen gets closer to implementation, the correspondent authorities are reviewing the trade rules.

The Effect of κ-Carrageenan on Porcine Sperm Cryo-Survival

κ-Carrageenan is a sulfated polysaccharide from red seaweed with substantial antioxidant activities. This study aimed to investigate the effect of κ-Carrageenan treatment on frozen-thawed (FT) porcine semen quality. Therefore, the spermatozoa were diluted and cryopreserved in a freezing extender supplemented with 0 (control), 0.2, 0.4, 0.6, and 0.8 mg/mL κ-Carrageenan. Sperm kinematics were assessed immediately after thawing (AT) and post-incubation for 120 min. The viability, acrosome integrity, lipid peroxidation, mitochondrial membrane potential (MMP), and intracellular caspase activity were measured AT. The results indicated that 0.2 mg/mL κ-Carrageenan increased total and progressive motility AT and post-incubation for 120 min (p < 0.05). Moreover, the viable sperm percentage and MMP after 0.2 mg/mL treatment were higher than those after control and other κ-Carrageenan concentration treatments. The proportion of acrosome-intact spermatozoa was significantly higher after 0.2 and 0.4 mg/mL κ-Carrageenan treatment than that after control and other κ-Carrageenan concentration treatments. The intracellular caspase activity was not significantly different among the experimental groups. However, the MDA concentration after 0.2 mg/mL κ-Carrageenan treatment was lower (p < 0.05) than that after the control treatment. Taken together, adding κ-Carrageenan to the porcine semen freezing extender improved the FT sperm quality mainly by influencing membrane stability and protecting against oxidative stress.

MORN2 regulates the morphology and energy metabolism of mitochondria and is required for male fertility in mice

BACKGROUND

Mitochondria produce adenosine triphosphate through respiratory activities to power sperm differentiation and motility, and decreased mitochondrial respiratory activity can result in poor sperm motility and asthenospermia. The mitochondrial sheath is a component of the mid-piece of the sperm flagellum, and dysfunction of the sheath can reduce sperm motility and cause male infertility. The membrane occupation and recognition nexus-motif protein 2 (MORN2) is testis enriched in mice, and the MORN motif was reported to play a role in the regulation of bioelectrical signal homeostasis in cardiomyocytes.

METHODS

We generated Morn2-/- mice using CRISPR/Cas9 and evaluated the potential functions of MORN2 in spermiogenesis through histological analysis, fertility examination, RT-PCR, CASA, immunofluorescence, TUNEL, electron microscopy analysis, mitochondrial energy metabolism analysis, etc. RESULTS: The Morn2-/- mice were infertile, and their sperm showed severe motility defects. Morn2-/- sperm also had abnormal morphology characterized by bent heads, aberrant mitochondrial sheath formation, lower mitochondrial membrane potential, higher levels of reactive oxygen species, and decreased mitochondrial respiratory activity.

CONCLUSIONS

Our study demonstrates that MORN2 is essential for male fertility and indicates that MORN2 functions in mitochondrial sheath formation and regulates mitochondrial respiratory activity.

Eugenol alleviates acrylamide-induced rat testicular toxicity by modulating AMPK/p-AKT/mTOR signaling pathway and blood-testis barrier remodeling

This study aimed to investigate the effects of eugenol treatment on reproductive parameters in acrylamide (ACR)-intoxicated rats. The study evaluated alterations in relative testes and epididymides weights, sperm quality, serum hormonal status, seminal plasma amino acids, testicular cell energy and phospholipids content, oxidative and nitrosative stress parameters, adenosine monophosphate-activated protein kinase/ phosphoinositide 3-kinase/phosphor-protein kinase B/mammalian target of rapamycin (AMPK/PI3K/p-AKT/mTOR) signaling pathway, blood-testis barrier (BTB) remodeling markers, testicular autophagy and apoptotic markers, as well as histopathological alterations in testicular tissues. The results revealed that eugenol treatment demonstrated a significant improvement in sperm quality parameters, with increased sperm cell concentration, progressive motility live sperm, and a reduction in abnormal sperm, compared to the ACR-intoxicated group. Furthermore, eugenol administration increased the levels of seminal plasma amino acids in a dose-dependent manner. In addition, eugenol treatment dose-dependently improved testicular oxidative/nitrosative stress biomarkers by increasing oxidized and reduced glutathione levels and reducing malondialdehyde and nitric oxide contents as compared to ACRgroup. However, eugenol treatment at a high dose restored the expression of AMPK, PI3K, and mTOR genes, to levels comparable to the control group, while significantly increasing p-AKT content compared to the ACRgroup. In conclusion, the obtained findings suggest the potential of eugenol as a therapeutic agent in mitigating ACR-induced detrimental effects on the male reproductive system via amelioration of ROS-mediated autophagy, apoptosis, AMPK/p-AKT/mTOR signaling pathways and BTB remodeling.

Punicalagin Protects Ram Sperm from Oxidative Stress by Enhancing Antioxidant Capacity and Mitochondrial Potential during Liquid Storage at 4 °C

The aim of this study was to investigate the effect of punicalagin, an antioxidant, on ram sperm quality. Semen samples were collected and pooled from five rams, then diluted using a Tris-based diluent containing various concentrations (0, 5, 15, 30 and 45 μM) of punicalagin. Sperm motility, plasma membrane integrity, acrosome integrity, total antioxidant capacity (TAC), reactive oxygen species (ROS), malondialdehyde (MDA), mitochondrial membrane potential (MMP), superoxide dismutase (SOD) and catalase (CAT) were measured and analyzed during liquid storage at 4 °C. The results showed that the Tris-based solution containing punicalagin improved sperm motility, plasma membrane integrity, acrosome integrity, TAC, SOD, CAT and MMP, and decreased ROS content and MDA content. At the same time, the semen sample diluted with the Tris-based solution supplemented with 30 μM punicalagin achieved the best effect. The sperm total motility, progressive motility, plasma membrane integrity, acrosome integrity, TAC, SOD, CAT and MMP of the group supplemented with 30 μM punicalagin were significantly (p < 0.05) higher than those of the other groups on the 5th day during the liquid storage at 4 °C. Meanwhile, the ROS content and MDA content were significantly (p < 0.05) lower than those in the other groups. In conclusion, the optimal concentration of punicalagin in the Hu ram semen diluent was determined to be 30 μM. The results indicated that a diluent supplemented with punicalagin could enhance the quality of ram sperm preserved at 4 °C by increasing antioxidant capacity, mitochondrial potential and reducing oxidative stress.

Effects of Nobiletin supplementation on the freezing diluent on porcine sperm cryo-survival and subsequent in vitro embryo development

Nobiletin (NOB) is a bioflavonoid compound isolated from citrus fruit peels. The present study aimed to elucidate whether NOB facilitates the porcine sperm cryosurvival and embryo development after in vitro fertilization (IVF). To this end, spermatozoa were diluted and cryopreserved in a freezing extender supplemented with 0 (control), 50, 100, 150, and 200 μM Nobiletin. The kinematic patterns of frozen-thawed (FT) sperm were assessed after 30 and 90 min incubation using a Sperm Class Analyzer (SCA). Viability, acrosome integrity, and mitochondrial membrane potential (MMP) were measured by fluorescence microscopy 30 min after thawing using SYBR-14/PI, PSA/FITC, and R123/PI, respectively. Lipid peroxidation was determined using MDA assay after incubation for 90 min. The addition of 100 μM and 150 μM NOB to the extender significantly improved sperm progressive motility, and acrosome integrity compared to the control group (P < 0.05). The proportion of viable spermatozoa was significantly higher in the 150 μM NOB group. MDA levels were less in 50 μM and 150 μM NOB treated groups compared to the control. In addition, IVF with FT sperm was used to assess the embryo developmental competence. Treatment with 150 μM NOB before cryopreservation increased the cleavage and blastocyst formation rates compared to the control group. Furthermore, the relative expression of POU5F1 and AMPK, genes related to pluripotency and cell differentiation were significantly upregulated in embryos resulting from NOB-treated sperm compared to the control group. These results suggest that Nobiletin is a functionally novel phytochemical to mitigate oxidative stress during the freezing-thawing of porcine spermatozoa as reflected by improved FT sperm quality and IVF outcome.

Chlorophytum borivilianum aqueous root extract prevents deterioration of testicular function in mice and preserves human sperm function in hydrogen peroxide (H2O2)-induced oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Chlorophytum borivilianum (C. borivilianum) (CB) has traditionally been used to treat male sexual dysfunctions and has been claimed to possess aphrodisiac properties.

AIM OF THE STUDY

To investigate the ability of CB to ameliorate H2O2-induced oxidative stress in testes and sperm in mice and prevent H2O2-induced oxidative in human sperm.

MATERIALS AND METHODS

Oxidative stress was induced in male mice by pre-exposure to 2% H2O2 orally for seven consecutive days, followed by 100 and 200 mg/kg b. w. administration. CB for another seven days. At the end of treatment, mice were sacrificed and testes and epididymal sperm were harvested. Serum FSH, LH and testosterone levels were measured and sperm parameters were obtained. Meanwhile, oxidative stress levels in mice testes and sperm, steroidogenesis and spermatogenesis markers in mice testes were assessed by molecular biological techniques. In another experiment, sperm from thirty-two healthy fertile men were incubated with 200 μM H2O2 and CB (100 and 200 μg/ml) simultaneously and were then evaluated for sperm parameter changes.

RESULTS

In mice, CB administration ameliorates persistent increases in oxidative stress and decreases in anti-oxidative enzyme levels in testes and sperm following H2O2 pre-exposure. Additionally, CB also helps to ameliorate deterioration in sperm parameters and testicular steroidogenesis and spermatogenesis and restores the serum FSH, LH and testosterone levels near normal in mice. In humans, CB helps to prevent deterioration in sperm parameters following H2O2 exposure.

CONCLUSION

CB is potentially useful to preserve the male reproductive capability and subsequently male fertility in high oxidative stress conditions.

Alpha-lipoic acid improves the quality of ram spermatozoa stored at 4°C by reducing oxidative stress and increasing mitochondrial potential

Introduction

Ram spermatozoa inevitably produce a large number of reactive oxygen species (ROS) during liquid storage, leading to oxidative stress and a decline of spermatozoa quality. Therefore, it is particularly important to add exogenous antioxidants during the process of semen liquid preservation. The purpose of this study is to investigate whether adding alpha-lipoic acid (ALA) to ram semen can reduce oxidative stress and enhance spermatozoa quality during the liquid storage at 4°C.

Methods

Different concentrations of ALA (0, 0.025, 0.05, 0.1, 0.5, 1 mM) were added to semen and stored at 4°C. During storage at 4°C, spermatozoa motility, kinetic parameters, membrane integrity, acrosome integrity, energy metabolism parameters (mitochondrial membrane potential (ΔΨM) and adenosine triphosphate (ATP)) and oxidative stress parameters [ROS, malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD)] were assessed.

Results and discussion

The results indicated that 0.1 mM ALA significantly (p<0.05) improved spermatozoa total motility (TM) and progressive motility (PM), plasma membrane integrity, acrosome integrity, ΔΨM, ATP, TAC, and SOD, while significantly (p<0.05) reducing spermatozoa ROS and MDA content compared to the control group. In conclusion, ALA can reduce damage caused by oxidative stress in spermatozoa and effectively improve the quality of semen preserved at 4°C. And the optimal concentration is 0.1 mM.

Nut Consumption and Fertility: a Systematic Review and Meta-Analysis

The high concentration of omega-3 polyunsaturated fats, dietary fibers, vitamins, minerals, and polyphenols found in nuts suggest their regular consumption may be a simple strategy for improving reproductive health. This systematic review and meta-analysis aimed to present up-to-date evidence regarding the association between nut intake and fertility outcomes in males and females. Ovid MEDLINE, Embase, CINAHL, and Scopus were searched from inception to 30 June 2023. Eligible articles were interventional or observational studies in human subjects of reproductive age (18-49 y) that assessed the effects (or association) of dietary nut consumption (for a minimum of 3 mo) on fertility-related outcomes. Random-effects meta-analyses were completed to produce a pooled effect estimate of nut consumption on sperm total motility, vitality, morphology, and concentration in healthy males. Four studies involving 875 participants (646 males, 229 females) were included in this review. Meta-analysis of 2 RCTs involving 223 healthy males indicated consumption of ≥ 60g nuts/d increased sperm motility, vitality, and morphology in comparison to controls but had no effect on sperm concentration. Nonrandomized studies reported no association between dietary nut intake and conventional sperm parameters in males, embryo implantation, clinical pregnancy or live birth in males and females undergoing ART. Our meta-analysis shows that including at least 2 servings of nuts daily as part of a Western-style diet in healthy males improves sperm parameters, which are predictors of male fertility. Due to their nutritional profile, nuts were found to have potential to promote successful reproductive outcomes. This trial was registered at PROSPERO (CRD42020204586).

Mammalian embryo culture media: now and into the future

For over 70years, since the culture of the first mammalian embryo in vitro , scientists have undertaken studies to devise and optimise media to support the manipulation and culture of gametes and embryos. This area of research became especially active in the late 1970s onwards following the successful birth of the first human in vitro fertilised embryo. This review summarises some of the key advances in mammalian embryo culture media over time based on a greater understanding of the biochemical milieu of the reproductive tract. It highlights how learnings from studies in mice and agricultural species have informed human culture media compositions, in particular the inclusion of albumin, growth factors, cytokines, and antioxidants into contemporary culture media formulations, and how these advances may then in turn help to inform and guide development of in vitro culture systems used in other arenas, in particular agriculture. Additionally, it will highlight how the introduction of new technologies, such as timelapse, can influence current trends in media composition and usage that may see a return to a single step medium.

Oleaster oil (Olea europaea sylvestris) effects on the efficiency of the reproductive system of diet-induced obese male Wistar rats

OBJECTIVES

Obesity is the result of oxidative stress (OS), which appears to be linked to male infertility. Oleaster oil has multiple therapeutic virtues due to its richness in natural bioactive compounds. This study aimed to evaluate the effect of Algerian oleaster oil on the reproductive system effectiveness of diet-induced obese male Wistar rats.

METHODS

The oil was extracted with an oleodoseur from the oleaster fruits. Rats were fed for 28 weeks two diets: a normal diet (NC group, n=8) and a high-fat, high-sucrose diet (HFHS group, n=32). The obese rats in the HFHS group were then split into three groups at random: the HFHS group, which continued to receive the HFHS diet; the HFHS L-OO group; and the HFHS H-OO group, which received for 6 weeks, respectively, in combination with the HFHS diet, oleaster oil at 1.5 and 3 mL/100 g body weight (BW). Then, the animals were sacrificed. Semen and testes were removed for semen analysis, OS, and histopathological evaluation.

RESULTS

The oleaster oil diet induces an improvement in sperm count and viability and a decrease in the percentage of fragmented sperm DNA compared to the group fed the HFHS diet, preserving the testes against OS with a highly significant decrease in testicular MDA. This beneficial effect of oleaster oil on the reproductive efficiency of rats fed the HFHS diet was dose-dependent.

CONCLUSIONS

The results showed that the oil decreased body weight, prevented OS and improved male reproductive indicators in HFHS-fed animals. The potential positive effects of oleaster oil on fertility biomarkers may be attributed to its ability to mitigate OS.

Omega 6/Omega 3 Ratio Is High in Individuals with Increased Sperm DNA fragmentation

An imbalance between omega-6 and omega-3 fatty acids in sperm has been linked with lipid peroxidation and DNA damage in sperm, indicating a possible correlation to fertility potential. This cross-sectional study involved 56 infertile men (aged 25-45), and assessed the relationship between the omega-6 to omega-3 fatty acid ratio in sperm and seminal plasma with sperm DNA fragmentation. Individuals were categorized based on high or low levels of sperm DNA fragmentation according to two tests (TUNEL and SCSA assay less or greater than 10 and 30%, respectively), and their fatty acid composition, as well as sperm functional tests, were analyzed. Results showed that men with high DNA fragmentation exhibited higher percentages of total saturated, monounsaturated, and omega-6 to omega-3 fatty acid ratios in both sperm (P < 0.001) and seminal plasma (P < 0.001) compared to men with low DNA fragmentation. The percentage of sperm lipid peroxidation, and residual histone (P < 0.05) were higher, while the percentage of sperm motility (P < 0.001) was lower in the former compared to the latter group. Moreover, Pearson's correlation revealed positive associations between the omega-6 to omega-3 fatty acid ratio with sperm lipid peroxidation, DNA fragmentation, and residual histones in both sperm and seminal plasma. Overall, these observations suggest that consumption of omega-3 fatty acids may be related to male fertility potential, as it appears that individuals with a high percentage of omega-3 fatty acids have better sperm quality compared to men with a lower omega-3 fatty acid.

Omega-3 with and without insulin replacement alleviates detrimental effects of type II diabetes on reproductive system of male C57BL/6 mice

AIMS

this study aimed to examine the protective role of omega-3 and insulin on reproductive system of the male mouse model of type II diabetes mellitus (T2DM), especially DNA integrity and chromatin quality.

MAIN METHODS

adult age-matched mice were divided into intact, sham, or T2DM groups (n = 7) which received a high-fat diet/low-dose streptozotocin. T2DM-induced animals underwent no treatment as diabetic control (T2DM), received omega-3 (T2DM + Omg3), received insulin (T2DM + Ins) and their combination (T2DM + Omg3 + Ins) for 35 days. After which, testicular and sperm parameters and testosterone levels were evaluated.

KEY FINDINGS

our findings revealed that the various examined parameters were comparable between the intact and sham groups, while most testicular and sperm parameters were affected by T2DM. Treatment of T2DM-induced animals with omega-3, alone and in combination with insulin, significantly improved sperm motility, normal morphology, sperm chromatin quality, DNA integrity, Leydig cell number and non-significantly testosterone levels.

SIGNIFICANCE

T2DM interferes with spermatogenesis and steroidogenesis as well as sperm quality and DNA integrity, which can be partially ameliorated by long-term administration of omega-3 in combination with or without insulin. Although our findings should be confirmed in clinical studies, since previous clinical trials have found omega-3 consumption to be beneficial in humans, its use seems to be safe and effective.

Protective effect of ligustrazine on oxidative stress and apoptosis following testicular torsion in rats

Testicular torsion is a common urologic emergency and one of the causes of infertility in males. It has been reported that ligustrazine may decrease oxidative stress and reduce ischemia-reperfusion injury. This study aims to investigate the protective effect of ligustrazine in ischemia-reperfusion injury after testicular torsion-detorsion. First, 40 rats were randomly and equally divided into TMP (Ligustrazine) group, the Testicular torsion (T/D) group, the Sham (Sham operation) group, and Control group. The left testis of rats in the TMP and T/D group was rotated for 2 h. The TMP group was intraperitoneally injected with ligustrazine solution and the T/D and the Sham groups were injected with normal saline. The left testes of four groups were obtained for assay on the 4th day after the operation. Average level of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) were higher in Sham and Control groups than T/D group and TMP group. Conversely, average level of malondialdehyde (MDA) and reactive oxygen species (ROS) was lower in Sham and Control groups than T/D group and TMP group. In contrast with the T/D group, SOD, GPX, and CAT enzymatic activities increased, whereas MDA and ROS content decreased in the TMP group (P < 0.05). Microscopic observation showed that the testicular tissue of the Sham and Control groups were basically normal. The TMP and T/D groups had significant testicular tissue damage, whereas the TMP group had less damage and apoptosis than the T/D group. The apoptotic index of germ cells in the TMP group (13.05 ± 4.41) was lower than the T/D group (30.23 ± 11.31) (P < 0.05) and higher (P < 0.05) than the Sham group (0.56 ± 0.29). So we found that Ligustrazine lowered ischemia-reperfusion injury after testicular torsion-detorsion by decreasing the reactive oxygen species and suppressing apoptosis.

The role of seminal reactive oxygen species assessment in the setting of infertility and early pregnancy loss

The male contribution to a couple suffering with adverse early pregnancy outcomes is being increasingly investigated. Seminal oxidative stress is considered to cause sperm DNA damage, thus affecting the functional capacity of the sperm. Multiple lines of evidence support an association between elevated seminal reactive oxygen species (ROS) and infertility. In the setting of assisted reproduction various factors in the in vitro environment, differing from the in vivo environment, may exacerbate oxidative stress. Furthermore, seminal ROS levels have been found to be higher in the male partners of couple's affected by both spontaneous and recurrent pregnancy loss. There are several methods by which to assess ROS levels however they are costly, inconsistent and their incorporation into clinical practice is unclear. The value of ROS assessment lies in the ability to plan targeted therapies to improve pregnancy and live birth rates. As such, further robust study is required before firm conclusions can be made to inform clinical practice. We aim to review the available evidence regarding the role of seminal ROS in infertility and pregnancy loss.

Oxidative Stress and Male Infertility: The Protective Role of Antioxidants

Oxidative stress is a significant factor in male infertility, compromising sperm function and overall reproductive health. As male infertility garners increasing attention, effective therapeutic interventions become paramount. This review investigates the therapeutic role of antioxidants in addressing male infertility. A detailed examination was conducted on antioxidants such as vitamin C, E, B12, D, coenzyme Q10, zinc, folic acid, selenium, l-carnitine, l-arginine, inositols, and alpha-lipoic acid. This analysis examines the methodologies, outcomes, and constraints of current clinical studies. Antioxidants show notable potential in counteracting the negative effects of oxidative stress on sperm. Based on the evidence, these antioxidants, individually or synergistically, can enhance sperm health and reproductive outcomes. However, certain limitations in the studies call for careful interpretation. Antioxidants are integral in tackling male infertility attributed to oxidative stress. The current findings underscore their therapeutic value, yet there's a pressing need for deeper, comprehensive research. Future studies should focus on refining dosage guidelines, identifying potential side effects, and discerning the most efficacious antioxidant combinations for male infertility solutions.

Prepubertal oral exposure to relevant doses of acrylamide impairs the testicular antioxidant system in adulthood, increasing protein carbonylation and lipid peroxidation

The increased prevalence of human infertility due to male reproductive disorders has been linked to extensive exposure to chemical endocrine disruptors. Acrylamide (AA) is a compound formed spontaneously during the thermal processing of some foods that are mainly consumed by children and adolescents. We previously found that prepubertal exposure to AA causes reduced sperm production and functionality. Oxidative stress is recognized as the main cause of reduced sperm quality and quantity. In this sense, our objective was to evaluate the expression and activity of genes related to enzymatic antioxidant defense, nonprotein thiols, lipid peroxidation (LPO), protein carbonylation (PC) and DNA damage in the testes of rats exposed to acrylamide (2.5 or 5 mg/kg) from weaning to adult life by gavage. For the AA2.5 and AA5 groups, there were no alterations in the transcript expression of genes related to enzymatic antioxidant defense. The enzymatic activities and metabolic parameters were also not affected in the AA2.5 group. For the AA5 group, the enzymatic activities of G6PDH and GPX were reduced, SOD was increased, and protein carbonylation (PC) was increased. Data were also evaluated by Integrate Biomarker Response (IBRv2), a method to analyze and summarize the effects on biomarkers between doses. The IBRv2 index was calculated as 8.9 and 18.71 for AA2.5 and AA5, respectively. The following biomarkers were affected by AA2.5: decreased enzymatic activities of G6PDH, SOD, and GPX, increased GST and GSH, increased LPO and PC, and decreased DNA damage. For AA5, decreased enzymatic activities of G6PDH, GST, CAT and GPX, increased SOD and GSH, increased PC, and decreased LPO and DNA damage were observed. In conclusion, AA exposure during the prepubertal period causes imbalances in the testicular enzymatic antioxidant defense, contributing to the altered spermatic scenario in the testes of these rats.

Effects of Different Diluents on Semen Quality of Hu Ram Stored at 4 °C

This study aimed to investigate the effects of various diluents on the quality of Hu ram sperm stored at 4 °C. Semen samples were collected from three Hu rams and diluted with diluents A (Sodium citrate-Glucose-Egg yolk), B (Sodium citrate-Glucose), C (Fructose-Skimmed milk powder-Soy lecithin), and D (Tris-Fructose-Citric acid-Egg yolk). Total motility (TM), straight-line velocity (VSL), average path velocity (VAP), curvilinear velocity (VCL), average motion degree (MAD), acrosome integrity, membrane integrity, and reactive oxygen species (ROS) were evaluated. The results showed that diluent D had better preservation in terms of the sperm TM, VSL, VCL, VAP, MAD, and membrane and acrosome integrity. On the third day of the storage, the sperm PM of diluent D was higher than that of other diluents (p < 0.05). The ROS level of diluent D was lower than that of other diluents on the fifth day (p < 0.05). On the seventh day of the storage, the sperm TM in diluent D reached 50%, which was the highest in all diluent groups. On the seventh day of the storage, the integrity of the sperm membrane and the integrity of the acrosome of the sperm in diluent D were the highest in all diluent groups (p < 0.05). In conclusion, these results indicated that diluent D improved the semen quality during storage at 4 °C. In this study, diluent D was the best diluent formula for Hu ram semen stored at 4 °C.

The Beneficial Effects of Pterostilbene on Post-Thawed Bovine Spermatozoa

Reactive Oxygen Species (ROS), primarily produced by cellular metabolism, are highly reactive molecules that modify cellular compounds. During sperm preparation in Assisted Reproductive Techniques (ARTs), intrinsic and extrinsic sources of ROS can impact spermatozoa's oxidative status. The modification of the media with compounds that enhance sperm quality characteristics is of great significance. The current study investigated the effect of pterostilbene, a phenolic compound, on bovine sperm quality. Cryopreserved spermatozoa from six bulls were thawed, supplemented with pterostilbene (0, 10 μΜ, 25 μΜ) and incubated for 60 min and 240 min. Spermatozoa were analyzed in terms of motility, viability, acrosomal status and intracellular concentration of superoxide anion in each time point. The incubation of spermatozoa with 25 μΜ pterostilbene resulted in the preservation of quality parameters through superoxide anion mitigation, while its presence in capacitating conditions resulted in higher percentage of acrosome-reacted spermatozoa. The results of the present study indicate that the addition of pterostilbene prevents oxidative insult to spermatozoa and preserves the sperm quality parameters.

Decreased Klotho Expression Causes Accelerated Decline of Male Fecundity through Oxidative Injury in Murine Testis

Oxidative stress is the etiology for 30-80% of male patients affected by infertility, which is a major health problem worldwide. Klotho protein is an aging suppressor that functions as a humoral factor modulating various cellular processes including antioxidation and anti-inflammation, and its dysregulation leads to human pathologies. Male mice lacking Klotho are sterile, and decreased Klotho levels in the serum are observed in men suffering from infertility with lower sperm counts. However, the mechanism by which Klotho maintains healthy male fertility remains unclear. Klotho haplodeficiency (Kl+/-) accelerates fertility reduction by impairing sperm quality and spermatogenesis in Kl+/- mice. Testicular proteomic analysis revealed that loss of Klotho predominantly disturbed oxidation and the glutathione-related pathway. We further focused on the glutathione-S-transferase (GST) family which counteracts oxidative stress in most cell types and closely relates with fertility. Several GST proteins, including GSTP1, GSTO2, and GSTK1, were significantly downregulated, which subsequently resulted in increased levels of the lipid peroxidation product 4-hydroxynonenal and apoptosis in murine testis with low or no expression of Klotho. Taken together, the loss of one Kl allele accelerates male fecundity loss because diminished antioxidant capability induces oxidative injury in mice. This is the first study that highlights a connection between Klotho and GST proteins.

Effects of Heterologous Bovine Seminal Plasma-Supplemented Egg Yolk-Based Extender on Cryosurvivability of Pantja Buck Semen

The present study was conducted to observe the effects of removal of seminal plasma of Pantja buck semen and supplementation of bovine seminal plasma (BSP) in the extender before cryopreservation. In a preliminary experiment, different levels of BSP were supplemented (1, 3, 5, 7, and 9% v/v) in egg yolk (7.5% egg yolk)-tris (EYT) extender and used for cryopreservation of Pantja buck semen. Results in terms of motility, viability, plasma membrane integrity, acrosome integrity, and lipid peroxidation showed that 5% BSP was suitable for maintaining Pantja buck semen quality during cryopreservation. In the final experiment, pooled semen from four Pantja bucks was split into three aliquots (I, II, and III). Aliquot I was directly diluted in EYT extender and grouped as the control (C); aliquot II and III were washed separately with TALP solution and diluted as D1 (Washed semen with EYT extender) and D2 (Washed semen with EYT extender containing 5% BSP), respectively. Seminal attributes (sperm individual motility, viability, plasma membrane integrity, acrosome integrity, and total morphological abnormalities) were assessed at the postdilution, postequilibration, and post-thawing stages. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA) concentration, and glutathione peroxidase (GSH-Px) activity were measured at post-thaw. Washed semen significantly improved (p < 0.05) seminal parameters at post-thaw compared with unwashed semen (control). A significant difference (p < 0.05) was observed in seminal attributes between freezing stages and between dilution groups. Significantly higher (p < 0.05) post-thaw sperm motility, viability, plasma membrane integrity, acrosome integrity, and GSH-Px activity, and significantly lower (p < 0.05) MDA concentration and extracellular release of enzymes (ALT, AST) were observed in group D2 compared with control and D1. The results of the present study demonstrated that cryopreservation of washed Pantja buck semen diluted with 5% BSP-supplemented EYT extender can improve post-thaw semen quality.

Role of oxidative stress in male infertility

Abstract

Infertility affects millions of couples worldwide. Oxidative stress (OS) causes peroxidation of lipids and damage to spermatozoa, thus, reducing the quality of seminal parameters. In addition, the differences in the levels of antioxidants and reactive oxygen species (ROS) caused by intrinsic and extrinsic variables linked to lifestyle, diet, genetics, and OS also contribute to male infertility. High levels of ROS result in sperm damage of sperm parameters due to lipid peroxidation and oxidation of proteins. Other significant causes of ROS include changes in sex hormone levels, sperm DNA damage, including mutations, and immature spermatozoa. Treating the root causes of OS, by changing one's lifestyle, as well as antioxidant therapy, may be helpful strategies to fight OS-related infertility. However, the determination of male infertility induced by OS is currently a challenge in the field of reproductive health research. This review intends to describe the role of oxidative stress on male infertility and the current understanding of its management.

Lay summary

The inability to conceive affects many couples globally. Oxidative stress refers to imbalances between different oxygen species which can lead to male fertility problems by damaging sperm and semen. Oxidative stress may be caused by several factors, including diets high in fats, sugars and processed foods, lifestyle (including smoking, alcohol consumption and having a sedentary lifestyle), and genetics. Treatment that focuses on the root cause may help combat male infertility. However, there is currently no consensus on the best way to treat male fertility problems, particularly those associated with oxidative stress. This paper describes the role of oxidative stress on male infertility and discusses the current techniques employed in treating male fertility issues.

The Impact of Oxidative Stress on Male Reproductive Function: Exploring the Role of Antioxidant Supplementation

Male reproductive function is highly susceptible to oxidative stress, which arises from an imbalance between reactive oxygen species (ROS) production and antioxidant defense mechanisms. Oxidative stress can significantly impair sperm quality, including count, motility, morphology, and DNA integrity, leading to male infertility. Antioxidants play a crucial role in maintaining reproductive health by neutralizing ROS and protecting sperm cells from oxidative damage. This review article explores the impact of oxidative stress on male reproductive function and investigates the potential benefits of antioxidant supplementation in mitigating its detrimental effects. A comprehensive literature search was conducted to gather relevant studies examining the effects of oxidative stress on male fertility and the outcomes of antioxidant supplementation. The findings reveal that antioxidant supplementation can improve sperm quality, DNA integrity, and fertility outcomes in some individuals. However, conflicting research findings and limitations in study design highlight the need for further investigation. Factors such as individual variations, underlying causes of infertility, dosage, and duration of supplementation should be carefully considered. Lifestyle modifications, including a healthy diet and exercise, are crucial in reducing oxidative stress and optimizing male reproductive health. This review article provides valuable insights into the complex relationship between oxidative stress and male reproductive function, emphasizing the potential role of antioxidant supplementation as a supportive strategy. Further research is warranted to establish optimal protocols, identify specific subgroups that may benefit the most, and explore advancements in antioxidant therapies to improve male fertility outcomes.

Impact of latent toxoplasmosis on the fertility indices of male rats

Infertility is a prevalent condition affecting approximately 70 million people worldwide and male factor contributes to about fifty percent of the issues. Studies on infectious agents as a possible cause of infertility has become prominent in the past decade. Toxoplasma gondii has emerged as a prime candidate as it has been found in the reproductive organs and semen of males of many animal species and humans. The aim of this study is to assess the effect of latent toxoplasmosis on experimental rat fertility. Ninety Toxoplasma infected rat were used as the experimental group besides, thirty control naïve ones. Both groups were observed clinically. Weekly assessment of fertility indices starting from the 7th week post infection till the 12th week were done by recording rat body weight, weight of testes, semen analysis and histo-morphometric analysis of the testes. Toxoplasma infected rats exhibited significant gradual loss of body weight and the absolute weight of the testes. The sperm characteristic parameters including percentage of motile sperm, percentage of viable sperm and sperm concentration in Toxoplasma infected rats showed highly significant decrease throughout the observation period in comparison to the control group with recording highly significant increase in the percentage of abnormal sperm forms. Pathological insults in tests of the infected rat group were denoted. Our findings demonstrated that Toxoplasma gondii is accused for affecting male rat main reproductive parameters and is implicated in the male reproductive disorders.

Effect of sulforaphane on long-term storage of rabbit semen

In this study, it was aimed to determine the effect of sulforaphane (SFN) on rabbit semen cryopreservation. Semen collected from animals was divided into 5 equal volumes as Control, SFN 5 µM, SFN 10 µM, SFN 25 µM and SFN 50 µM groups. Afterwards, semen analyzes were performed. According to our results, there was no statistical difference between the groups at 4°C. However after freezing thawing, the highest total motility, progressive motility and rapid spermatozoa rate was seen in the 10 µM SFN group, while the lowest was observed in the 50 µM SFN group (P<0.05). Static sperm ratio was highest in the 50 µM group, while the lowest was observed in the 10 µM SFN group. When flow cytometry results examined the rate of acrosomal damaged and dead sperm was the lowest in the 10 µM SFN group, a statistical difference was observed between the control group (P<0.05). The highest rate of sperm with high mitochondrial membrane potential was seen in the 5 µM SFN and 10 µM SFN groups. Apoptosis and ROS rates were found to be lower in the experimental groups compared to the control groups (P<0.05). As a result, SFN supplementation at a dose of 10 µM increased the quality of sperm in the freezing and thawing processes of rabbit semen. In conclusion, 10 µM SFN improved the quality of cryopreservation of rabbit semen.

Therapeutic potential of testosterone on sperm parameters and chromatin status in fresh and thawed normo and asthenozoospermic samples

BACKGROUND

Hormonal changes alter the physiological level of ROS and cause oxidative stress in the cell. As estimated, hormonal deficiencies, environmental and ideological factors make up about 25% of male infertility. Pathogenic reactive oxygen species (ROS) is a chief cause of unexplained infertility. Limited studies exist on the effects of testosterone on human sperm culture. Therefore, in the current study, the effect of different doses of testosterone on sperm parameters and chromatin quality was investigated.

MATERIALS AND METHODS

Semen samples from 15 normospermic and 15 asthenospermic patients were prepared by swim up method, and then were divided into four groups by exposing to different concentrations of testosterone (1, 10, and 100nM) for 45min. Samples without any intervention were considered as control group. All samples were washed twice. Sperm parameters and chromatin protamination were assessed in each group and the remains were frozen. After two weeks, all tests were repeated for sperm thawed. Also, the MSOM technique was used to determine the sperm morphology of class 1.

RESULTS

Although sperm parameters were not show any significant differences in normospermic and asthenospermic samples exposed to different concentrations of testosterone before and after freezing, chromatin protamination was significantly decreased in the normospermic samples exposed to 10nM of testosterone before freezing (p<0.006), as well as 1 and 10nM of testosterone after freezing compared to control samples (p=0.001 and p=0.0009, respectively). Similarly, chromatin protamination in the asthenospermic samples was significantly decreased at concentration of 1nM of testosterone before and after freezing (p=0.0014 and p=0.0004, respectively), and at concentration of 10nM of testosterone before and after freezing (p=0.0009, p=0.0007) compared to control samples.

CONCLUSION

Using a low dose of testosterone in the sperm culture medium, has positive effects on chromatin quality.

Effect of COVID-19 on sperm parameters: pathologic alterations and underlying mechanisms

The rapid outbreak of the coronavirus disease 2019 (COVID-19) pandemic has brought challenges to different medical fields, especially reproductive health. To date, most studies on the effects of COVID-19 on male reproduction have some limitations. In addition, there is little research on the mechanisms underlying by which severe acute respiratory syndrome coronavirus 2 infection affects semen quality. Here, we revealed the possible impact of COVID-19 on sperm parameters and the potential mechanisms. At present, it is still controversial whether COVID-19-induced fever adversely affects sperm parameters. Severe acute respiratory syndrome coronavirus 2 can induce up-regulation of pro-inflammatory cytokine, which leads to the destruction of blood-testis barrier and impairment of spermatogenesis. Moreover, severe viral infection of the respiratory system could induce systemic oxidative stress. Sperm are highly vulnerable to it due to their limited levels of antioxidant defense, unsophisticated DNA damage detection and repair mechanisms. Our review prompt medical staff and patients to consciously check the reproductive function of COVID-19 male patients. Moreover, opening our prospective beyond the direct infection could be the key to better understand the COVID-19 short and long-term effects and provide a new idea for future treatment of patients with reproductive function injury.

Analyzing the effect of heparin on in vitro capacitation and spermatozoal RNA population in goats

Heparin is a glycosaminoglycan polymer that is commonly used as an anticoagulant. Heparin also induces in vitro capacitation in spermatozoa, although its molecular mechanism is elusive. This study investigated the effect of heparin on in vitro capacitation and spermatozoal RNA (spRNA) population in goats. Goat spermatozoa were treated with 20 μM heparin for 0-6 h and evaluated for motility, capacitation, acrosome reaction, and spRNA population by RNA sequencing (RNA-seq). It was observed that heparin enhanced sperm motility up to 6 h of incubation (p < 0.05). Heparin also induced capacitation and acrosome reaction within 4 h. RNA-seq identified 1254 differentially expressed genes (DEGs) between heparin-treated and control spermatozoa. Most DEGs (1251 nos.) were upregulated and included 1090 protein-coding genes. A few genes (PRND, ITPR1, LLCFC1, and CHRM2) showed >5-fold increased expression in heparin-treated spermatozoa compared to the control. The upregulated genes were found to be involved in cAMP-PKA, PI3-Akt, calcium, MAPK signaling, and oxidative stress pathways. DCFDA staining confirmed the increased oxidative stress in heparin-treated spermatozoa compared to the control (p < 0.05). In conclusion, the results of the present study suggest that heparin enhances sperm motility and induces capacitation by upregulation of the spRNA population and oxidative stress pathway.

The Role of Seminal Oxidative Stress in Recurrent Pregnancy Loss

Recurrent pregnancy loss is a distressing condition affecting 1–2% of couples. Traditionally investigations have focused on the female, however more recently researchers have started to explore the potential contribution of the male partner. Seminal reactive oxygen species have a physiological function in male reproduction but in excess are suspected to generate structural and functional damage to the sperm. Evidence is mounting to support an association between elevated seminal reaction oxygen species and recurrent pregnancy loss. Studies suggest that the rates of sperm DNA damage are higher in the male partners of women affected by recurrent pregnancy loss compared with unaffected men. However, the available pool of data is conflicting, and interpretation is limited by the recent change in nomenclature and the heterogeneity of study methodologies. Furthermore, investigation into the effects of oxidative stress on the epigenome show promise. The value of antioxidant therapy in the management of recurrent pregnancy loss currently remains unclear.

Resveratrol Ameliorates Vancomycin-Induced Testicular Dysfunction in Male Rats

Background and Objectives: Numerous studies have indicated that antibiotics may adversely affect testicular and sperm function. As an alternative to penicillin, vancomycin is a glycopeptide antibiotic developed to treat resistant strains of Staphylococcus aureus. A few studies have suggested that vancomycin could cause testicular toxicity and apoptosis. Vancomycin, however, has not been investigated in terms of its mechanism of causing testicular toxicity. Materials and Methods: An experiment was conducted to investigate the effects of resveratrol (20 mg/kg, oral gavage) against vancomycin (200 mg/kg, i.p.) on the testicular function of Wistar rats for one week (7 days). There were three subgroups of animals. First, saline (i.p.) was administered to the control group. Then, in the second group, vancomycin was administered. Finally, vancomycin and resveratrol were administered in combination in the third group. Results: After seven days of vancomycin treatment, testosterone levels, sperm counts, and sperm motility were significantly reduced, but resveratrol attenuated the effects of vancomycin and restored the testosterone levels, sperm counts, and sperm motility to normal. In the presence of resveratrol, the vancomycin effects were attenuated, and the luteinizing hormone and follicular hormone levels were normalized after seven days of treatment with vancomycin. Histologically, vancomycin administration for seven days caused damage to testicular tissues and reduced the thickness of the basal lamina. However, the resveratrol administration with vancomycin prevented vancomycin’s toxic effects on testicular tissue. Conclusion: Resveratrol showed potential protective effects against vancomycin-induced testicular toxicity in Wistar rats.

The Association Between Lipid Serum and Semen Parameters: a Systematic Review

Increased lipid levels sometimes not only affect sexual function but also are considered to harm semen quality. It is often a suspicion that elevated lipids are a factor in infertility. We conduct a systematic review. Articles that met the criteria were identified according to The Preferred Reporting Items for Systematic Review and Meta-analysis of recommendations in the PubMed, ProQuest, EBSCO, Web of Science Wiley Online, Springer Link, Scopus, and Science Direct databases with no time restriction for publication. Seven studies are eligible for qualitative analysis from nine studies that have the potential to be assessed. These studies measure the correlation of serum lipids (VLDL, HDL, LDL, triglycerides, total cholesterol, free cholesterol, phospholipids, free fatty acids) with semen parameters (concentration, motility, morphology, DNA fragmentation index). Although not all studies consistently report that lipids impact semen quality, this review suspects that lipids have a significant impact on sperm quality. This study implies that it is necessary to maintain lipid levels to maintain sperm quality and quality of life. However, further investigation with an observational cohort study design needs to be carried out to assess the effect of lipids on semen quality more precisely for the promotion of reproductive health care.

Catechin versus MoS2 Nanoflakes Functionalized with Catechin: Improving the Sperm Fertilizing Ability-An In Vitro Study in a Swine Model

Nowadays, the adoption of In Vitro Fertilization (IVF) techniques is undergoing an impressive increase. In light of this, one of the most promising strategies is the novel use of non-physiological materials and naturally derived compounds for advanced sperm preparation methods. Here, sperm cells were exposed during capacitation to MoS₂/Catechin nanoflakes and catechin (CT), a flavonoid with antioxidant properties, at concentrations of 10, 1, 0.1 ppm. The results showed no significant differences in terms of sperm membrane modifications or biochemical pathways among the groups, allowing the hypothesis that MoS₂/CT nanoflakes do not induce any negative effect on the parameters evaluated related to sperm capacitation. Moreover, the addition of CT alone at a specific concentration (0.1 ppm) increased the spermatozoa fertilizing ability in an IVF assay by increasing the number of fertilized oocytes with respect to the control group. Our findings open interesting new perspectives regarding the use of catechins and new materials obtained using natural or bio compounds, which could be used to implement the current strategies for sperm capacitation.

A review of the use of antioxidants in bovine sperm preparation protocols

Reactive oxygen species (ROS) and oxidative stress (OS), the imbalance between the production of free radicals and the cellular antioxidant defenses, are discussed in relation to their role in bovine sperm physiology. Oxidative stress has been associated to male infertility and low fertility rates in Assisted Reproductive Techniques (ART). Antioxidant supplementation is an interesting approach to overcome OS-related infertility and assisted reproduction drawbacks. Several studies have been conducted to identify the potential sources of ROS in a typical ART setting and the impact of antioxidant supplementation on semen quality and pregnancy outcome. Procedures such as freezing and thawing, centrifugation and incubation are thought to produce significant amounts of ROS with a negative impact on sperm quality parameters and reproductive competence. Given the important role of ROS in sperm function, the addition of antioxidants in sperm media to prevent OS and to improve the reproductive outcome requires attention. Currently, there is limited evidence to support the ameliorative effect of antioxidant supplementation on fertilization and embryo development in farm animals. This review summarizes the different types and concentrations of antioxidants used in sperm preparation media of bovine species and their effectiveness in neutralizing excessive ROS production while preserving physiological sperm function.

Role of antioxidants in fertility preservation of sperm - A narrative review

Male fertility is affected by multiple endogenous stressors, including reactive oxygen species (ROS), which greatly deteriorate the fertility. However, physiological levels of ROS are required by sperm for the proper accomplishment of different cellular functions including proliferation, maturation, capacitation, acrosomal reaction, and fertilization. Excessive ROS production creates an imbalance between ROS production and neutralization resulting in oxidative stress (OS). OS causes male infertility by impairing sperm functions including reduced motility, deoxyribonucleic acid damage, morphological defects, and enhanced apoptosis. Several in-vivo and in-vitro studies have reported improvement in quality-related parameters of sperm following the use of different natural and synthetic antioxidants. In this review, we focus on the causes of OS, ROS production sources, mechanisms responsible for sperm damage, and the role of antioxidants in preserving sperm fertility.

Naringenin alleviate reproductive toxicity evoked by lead acetate via attenuation of sperm profile and biochemical alterations in male Wistar rat: Involvement of TGFβ/AKT/mTOR pathway

Exposure to Lead -causes testicular dysfunction through oxidative stress, inflammation, and apoptosis; however, naringenin (NGN) therapeutic impact against lead-evoked testicular dysfunction remains elusive. Herein, the point of the study was to examine the defensive impact of NGN on testicular dysfunction initiated by lead. Seventy-Two male Wistar rats were allotted into nine groups; control group, drug control groups, lead acetate group, as well as NGN treated groups (10, 25, and 50 mg/kg) respectively, given 5 days before lead acetate treatment. The result showed clearly the impact of lead on reduced sperm count, sperm motility as well as serum testosterone and LH levels. Additionally, it caused a significant rise in testicular inflammatory markers TNF-α, IL-1β, and TGFβ, effects that were accompanied by a reduction of AKT and mTOR levels. Lead acetate also caused degenerative changes in the testis, atrophy, and loss of spermatogenic series. Our findings revealed that NGN in a dose-dependent manner improved spermiotoxicity induced by lead acetate via restoration of the testicular function, preservation of spermatogenesis, halting inflammatory cytokines along with the enhancement of germ cell survival using upregulation of AKT/mTOR expressions. The present study discloses that NGN suppresses lead acetate toxicity that is involved in the antioxidant effect in a dose-dependent manner, besides its anti-inflammatory property.

Changes in Organ Weight, Sperm Quality and Testosterone Levels After Aluminum (Al) and Indium (In) Administration to Wistar Rats

BACKGROUND

Aluminum and indium are widely used in industrial manufacturing, in pharmaceutical products, in medical treatments, and in food packaging, so they could reach organisms by different way. In order to clarify whether these elements are dangerous, we already demonstrated the ultrastructural modifications observed in the testicles, the epididymides, and the seminal vesicles of rat. Their pro-oxidative effect was also confirmed concomitantly to a decrease in anti-oxidant defenses in the blood, the testicles, and the liver. Thus, it seemed very logic to evaluate damages in the reproductive organs, especially on the exocrine and endocrine functions of the testicles.

METHODS

Aluminum and indium were intraperitoneally administered to male Wistar rats. Sperm solution was obtained from cauda epididymides. Motility, viability, density, and malformation of spermatozoa solution were assessed. Serum total unconjugated testosterone concentrations were measured using RIA technique.

RESULTS

Our results showed a decrease in weight of the testicles, epididymides, and seminal vesicles of indium-treated rats and an increase in the weight of their kidneys. A decrease in motility, viability, and density of epididymides stored sperm as well as generation of many spermatozoa malformations was also observed especially in indium-treated rats. Testosterone levels were increased in indium but were enhanced in aluminum group. This confirmed our previous studies showing that aluminum and indium are toxic for the testicular tissues. This could be explained by the generation of reactive oxygen species (ROS) affecting strongly the exocrine and the endocrine functions of the testicles.

CONCLUSION

Aluminum and indium are disturbing elements for the exocrine and endocrine functions of rat testicles.

Evaluate effects of the dilution medium and holding time on various motility parameters of delta smelt semen

Sperm preservation is an efficient technique used for the recovery, conservation, and management of some endangered fish species. The present study was conducted to explore how preservation time would affect sperm and spawning performance in the endangered delta smelt (Hypomesus transpacificus). Sperm were preserved with the modified Hanks balanced salt solution at 14.7-16.9 °C. The Kruskal-Wallis test of sperm parameters using OpenCASA plugin in ImageJ software showed that sperm (n = 33♂) had significantly higher velocity and motility within the first 5 s after activation than that of other time points, while sperm had the lowest velocity and motility after 3 min post activation (P < 0.001). The findings (n = 30♂) also showed fresh sperm had higher velocity and motility than preserved sperm, while the sperm preserved for over 24 h showed a significantly low performance (P < 0.001). The nonlinear mixed effects models of fertilization results (n = 14♂ × 70♀) indicated the fresh sperm and sperm preserved for 1 h had higher fertilization rates than other preservation times (P < 0.001). The hatching rate (n = 14♂ × 70♀) also showed the fresh sperm and sperm preserved for 3 min and 1 h had higher hatching rates than other preservation times (P < 0.001). Overall, the study showed the best sperm performance in delta smelt was found within the first 5 s post activation, and the best fertilization and hatching rates were found when the sperm were fresh and preserved for 1 h. The findings of this study provide information for the first time about how long the delta smelt's sperm are motile for quality analysis, and how the preservation time can affect sperm quality, fertility, and hatching of this species for future applications.

Seasonal and climatic factors have a significant influence on fertility associated sperm phenomic attributes in crossbred breeding bulls (Bos taurus × Bos indicus)

Although seasonal variations in semen quality and fertility have been studied to a considerable extent in breeding bulls, the effect of climatic variables on sperm functional competency has not been understood in detail. The present study analyzed sperm functional parameters in breeding bulls, over a period of 1 year, and assessed the effect of climatic variables on fertility associated sperm parameters. Seasons were categorized into summer, rainy, autumn, and winter based on the meteorological data. Semen was collected from crossbred bulls (n = 7) across the seasons and evaluated for functional membrane integrity, acrosome reaction status, protamine deficiency, capacitation, and lipid peroxidation status using specific fluorescent probes. The results of the present study revealed that bulls produced higher (p < 0.05) viable and acrosome intact spermatozoa during the autumn. The proportion of uncapacitated spermatozoa was also higher (p < 0.05) during autumn. Further, correlation of sperm functional attributes with environmental variables revealed that sperm viability was significantly (p < 0.05) and negatively correlated with daylength and temperature; acrosomal integrity was significantly (p < 0.05) and negatively correlated with day length; and protamine deficiency had significant (p < 0.05) positive correlation with day length and average temperature, and negative correlation with relative humidity. It was concluded that semen produced during autumn was superior to the semen produced during other seasons in terms of sperm functional competencies required for fertility.

Hypothalamic-Pituitary-Gonadal Axis Disorders Impacting Fertility in Both Sexes and the Potential of Kisspeptin-Based Therapies to Treat Them

Impaired function of the hypothalamic-pituitary-gonadal (HPG) axis can lead to a vast array of reproductive disorders some of which are inherited or acquired, but many are of unknown etiology. Among the clinical consequences of HPG impairment, infertility is quite common. According to the latest report from the World Health Organization, the global prevalence of infertility during a person's lifetime is a staggering 17.5% which translate into 1 out of every 6 people experiencing it. In both sexes, infertility is associated with adverse health events, and if unresolved, infertility can cause substantial psychological stress, social stigmatization, and economic strain. Even though significant advances have been made in the management and treatment of infertility, low or variable efficacy of treatments and medication adverse effects still pose a significant problem. However, the discovery that in humans inactivating mutations in the gene encoding the kisspeptin receptor (Kiss1R) results in pubertal failure and infertility has expanded our understanding of the mechanisms underlying the neuroendocrine control of reproduction, opening up potential new therapies for the treatment of infertility disorders. In this chapter we provide an overview of common infertility disorders affecting men and women, their recommended treatments, and the potential of kisspeptin-based pharmacotherapies to treat them.

The first-line antituberculosis drugs, and their fixed-dose combination induced abnormal sperm morphology and histological lesions in the testicular cells of male mice

Rifampicin (RIF), Isoniazid (INH), Ethambutol (EMB), Pyrazinamide (PZA), and/or their fixed-dose combination (FDC) are extensively prescribed in the cure of Tuberculosis (TB) globally. In spite of the beneficial effect, these drugs are capable of inducing cellular toxicity. Existing information on the genotoxic effects of the first-line anti-TB drugs is limited and contentious. Herein, we evaluated the reproductive genotoxicity of RIF, INH, EMB, PZA, and their FDC utilizing the mouse sperm morphology assay. Histological examination of the testes of exposed mice was also performed. Male Swiss albino mice (11-13 weeks old) were intraperitoneally exposed for 5 consecutive days to each of the anti-TB drugs at four different doses of 6.25, 12.5, 25, and 50 mg/kg bw of PZA; 2.5, 5.0, 10, and 20 mg/kg bw of RIF; 1.25, 2.5, 5.0 and 10 mg/kg bw of INH; 3.75, 7.5, 15 and 30 mg/kg bw of EMB; and 7, 14, 28 and 56 mg/kg bw of FDC corresponding respectively to ×0.25, ×0.5, ×1 and ×2.0 of the standard daily dose. In comparison with the negative control (normal saline), there was no significant difference in the testicular weight and organo-somatic index of exposed mice. There was an increase (p > 0.05) in the frequency of abnormal spermatozoa at most of the tested doses of each drug and a dose-dependent decrease with the FDC. Each of the anti-TB drugs except the FDC induced pathological lesions in the testes. These findings suggest that the individual first-line anti-TB drug unlike the FDC has the potential to provoke testicular anomalies in male mice.

Cryopreservation of Yak Semen: A Comprehensive Review

An urgent need to boost the sustainability and efficiency of animal production exists, owing to the growing global population. Enhancing the global fertility of animals, especially cattle, is essential to ameliorate this issue. Artificial insemination and sperm cryopreservation have a considerable and favorable influence on the quantity and quality of the cattle produced. Sperm cryopreservation is crucial for livestock production because it promotes and accelerates genetic diversity and the worldwide dispersion of animals with enhanced genetics. Owing to the importance of cryobiology in reproductive technologies, researchers are developing new approaches, and they are testing cryoprotectant drugs to enhance sperm cryosurvival. However, the viability of sperm after freezing is low and widely varies across breeding yaks. These faults are crucial because they impede advances in reproductive biotechnology and the study of mammalian gametes at a fundamental level. Using chemicals, researchers have developed and enhanced various extenders with varying degrees of efficiency to reduce cryodamage and oxidative stress. In this article, we review the cryopreservation of yak semen, the development of extenders, the difficulties faced during cryopreservation, and the evaluation of semen quality using various methodologies. This review might be helpful for researchers exploring semen cryopreservation in the future, as demand for enhanced cryopreservation exists to boost the post-thaw viability and fertility of sperm.

Fertility in the aging male: a systematic review

The negative effect of advanced female age on fertility and offspring health is well understood. In comparison, much less is known about the implications of male age on fertility, with many studies showing conflicting results. Nevertheless, increasing evidence suggests that advanced paternal age has negative effects on sperm parameters, reproductive success, and offspring health. Herein, we summarize the current body of knowledge on this controversial topic, with the belief that this review will serve as a resource for the clinicians providing fertility counseling to couples with older male partners.

Mechanisms of Male Reproductive Toxicity of Polybrominated Diphenyl Ethers

Polybrominated diphenyl ethers (PBDE) are a group of flame retardants used in a variety of artificial materials. Despite being phased out in most industrial countries, they remain in the environment and human tissues due to their persistence, lipophilicity, and bioaccumulation. Populational and experimental studies demonstrate the male reproductive toxicity of PBDEs including increased incidence of genital malformations (hypospadias and cryptorchidism), altered weight of testes and other reproductive tissues, altered testes histology and transcriptome, decreased sperm production and sperm quality, altered epigenetic regulation of developmental genes in spermatozoa, and altered secretion of reproductive hormones. A broad range of mechanistic hypotheses of PBDE reproductive toxicity has been suggested. Among these hypotheses, oxidative stress, the disruption of estrogenic signaling, and mitochondria disruption are affected by PBDE concentrations much higher than concentrations found in human tissues, making them unlikely links between exposures and adverse reproductive outcomes in the general population. Robust evidence suggests that at environmentally relevant doses, PBDEs and their metabolites may affect male reproductive health via mechanisms including AR antagonism and the disruption of a complex network of metabolic signaling.