Lipid peroxidation, mitochondrial membrane potential and DNA integrity of spermatozoa in relation to intracellular reactive oxygen species in liquid and frozen-thawed buffalo semen

The Effect of Adding Different Levels of Reduced Glutathione to Extender on the Quality of Cooled Ring-Necked Pheasant Semen

Aim: Artificial propagation of ring-necked pheasant through semen preservation is of significance, as this species is facing enormous threats in its natural habitat. Semen preservation inevitably induces oxidative stress, and exogenous antioxidants need to be investigated for the preservation of ring-necked pheasant semen. Therefore, the current study was conducted to investigate the role of glutathione (GSH) in extender on the liquid storage of ring-necked pheasant semen. Materials and Methods: Semen was collected from 10 sexually mature males, evaluated for sperm motility, and pooled. Pooled semen was aliquoted for dilution with Beltsville poultry semen extender (1:5) at 37°C having GSH levels of 0.0 mM (Control), 0.2, 0.4, 0.6, and 0.8 mM. Extended semen was gradually cooled to 4°C and stored in a refrigerator (4°C) for 48 hours. Semen quality, that is, sperm motility, membrane integrity, viability, acrosomal integrity, and DNA integrity, was assessed at 0, 2, 6, 24, and 48 hours. Results: Sperm motility (%), plasma membrane integrity (%), viability (%), and acrosomal integrity (%) were recorded higher (p < 0.05), whereas DNA fragmentation (%) was recorded lower in extender supplemented with 0.4 mM GSH up to 48 hours of storage compared with 0.2, 0.6, and 0.8 mM GSH concentrations and control. Conclusion: It is concluded that 0.4 mM GSH in extender improves sperm quality parameters of ring-necked pheasant during liquid storage up to 48 hours at 4°C.

Effect of selenium nanoparticles on the quality and fertility of short-term preserved boar semen

This study was carried out to investigate the effect of different concentrations of selenium nanoparticles (Se-NPs) in the Beltsville Thawing Solution (BTS) extender on the semen quality and fertility of Hampshire crossbred pigs. For the study, semen was collected from four boars (10 ejaculates/boar) by the gloved hand method. Each ejaculate was extended @ 1:2 with the BTS extender and split into four aliquots. The control (C) samples were without the supplementation of Se-NPs, whereas the other three were supplemented with 0.5 (T1), 1 (T2), and 2 μg ml-1 of Se-NPs (T3) and stored at 15°C in a BOD incubator. Extended semen was evaluated at 0 (immediately after dilution), 24, 48, 72, and 96 h of storage for sperm motility, live sperm, plasma membrane integrity, acrosome integrity, DNA integrity, and mitochondrial membrane potential (MMP). The mean percentage of sperm motility, live sperm, and sperm with intact plasma membrane and acrosome, and MMPs were significantly (p < 0.01) higher in all treated groups in comparison to control at 24, 48, 72, and 96 h of storage. Sperm with intact DNA in all treated groups increased significantly at 48 (p < 0.05), and 72 and 96 (p < 0.01) h of storage in comparison to the control group. The concentration of 1 μg ml-1 of Se-NPs was found to be the best among other concentrations. In each group, 10 sows were artificially inseminated with the liquid semen preserved for 72 h at 15°C. Supplementation of 1 μg ml-1 of Se-NPs yielded the highest conception rate in comparison to other groups. In conclusion, supplementation of 1 μg ml-1 of Se-NPs in the BTS extender resulted in the best semen quality and conception rate during the short-time liquid preservation of boar semen.

Unveiling the impact of environmental microplastics on mussel spermatozoa: First evidence of prothymosin-α detection in invertebrate's male gametes

Mytilus galloprovincialis mussels, like many other marine invertebrates, employ external fertilization as a mating strategy, exposing their gametes to various contaminants upon release into seawater. Environmental microplastics (EMP) are prevalent marine pollutants that pose a significant threat to aquatic biota. In this regard, our study aimed to investigate the potential effects of exposing mussels' male gametes to increasing concentrations of EMP (1, 10, 50, and 100 μg/l) collected from a Mediterranean sandy beach. We focused on assessing gamete quality by analysing physiological parameters such as viability, mitochondrial membrane potential, oxidative status, and motility. Additionally, we evaluated DNA integrity and activation of apoptosis. Furthermore, our study aimed to detect the presence of the prothymosin-α (PTMA) protein, which has never been previously investigated in invertebrate spermatozoa. Our data revealed that exposure of mussel spermatozoa to EMPs altered their oxidative status and mitochondrial membrane potential, induced a decrease in motility, DNA integrity, and an increased apoptotic occurrence, leading to a decline in overall viability. The localization of PTMA into the head and flagellum of spermatozoa further supported its presence and susceptibility to the effects of microplastics. These findings raise concerns about the reproductive capacity of mussels under environmental microplastic pollution and highlight potential long-term threats to population sustainability.

Coenzyme Q10 improves the quality and in vitro fertility of post-thawed buffalo (Bubalus bubalis) semen via its antioxidative effect

This study aimed to determine the effects of Coenzyme Q10 (CoQ10) in the freezing medium on functional and oxidative stress parameters and in vitro fertilization (IVF) rate of buffalo sperm. Collected samples were relocated to the laboratory for initial evaluation, gentle dilution in extenders, cooling (4°C, 2 h), equilibration (4°C, 4 h), packaging (straws, 0.5 mL), programmable freezing, and thawing (37°C, 30 s). Statistical analysis depicted that adding CoQ10 (100 μM) in a freezing medium caused a significant augmentation in total motility (%), average path, and straight-line velocities (μm/sec) of buffalo sperm than control. Adding CoQ10 (100 μM) improved sperm progressive motility, rapid velocity, and functional parameters (%) compared to the control and 10 μM of CoQ10. Moreover, CoQ10 in a freezing medium caused a significant augmentation in seminal plasma catalase (U/mL) and glutathione reductase (GSH; nmol/109 ) at 100 μM than control and other treatments. CoQ10 inclusion (100 μM) ameliorates seminal plasma superoxide dismutase (U/mL), glutathione-S-transferase (GST; nmol/mL/min) fructose (μg/mL), and ATP (nmol/million) than control. Furthermore, CoQ10 at 100 μM improved seminal plasma glutathione peroxidase (μM) levels than control, 10 μM, and 20 μM. Lastly, hydrogen peroxide (H2 O2; nM) production was significantly lower at 100 μM than at control and 10 μM. CoQ10 (100 μM) caused a significant augmentation in the un-capacitated pattern followed by a reduction in the capacitated pattern, and apoptosis-like changes (%) than control, and other treatments, whereas viability was increased than control and other treatments. CoQ10 (100 μM) significantly improved the IVF rate in comparison with control, CoQ10 at 10 μM, and 20 μM groups. In conclusion, the addition of CoQ10 (100 μM) in the freezing medium can improve the quality and in vitro fertility of post-thawed buffalo semen via its antioxidative effect. Further studies are needed to evaluate the effect of CoQ10 on the in vivo fertility of buffalo bull semen.

Nano-quercetin mitigates triazophos-induced testicular toxicity in rats by suppressing oxidative stress and apoptosis

The present study was designed to evaluate the testicular toxicity of triazophos in rats and to check the ameliorative effect of nano-quercetin against triazophos-induced toxicity. Nano-quercetin was synthesized from quercetin and characterized. Male Wistar rats were divided into seven groups. The control group received olive oil as a vehicle orally. The high-dose triazophos group and the low-dose triazophos group received 1/10th LD50 of triazophos (7.6 mg/kg) and 1/20th LD50 of triazophos (3.8 mg/kg), respectively. Two groups of animals were dosed with quercetin and nano-quercetin, both at 50 mg/kg body weight orally. The final two groups received high-dose triazophos with co-administration of quercetin and nano-quercetin, respectively. Triazophos disrupted the male endocrine axis by reducing the levels of steroidogenic enzymes 3-β-HSD and 17-β-HSD in testicular cells, further reducing FSH and testosterone. Also, triazophos increased the reactive oxygen species, induced lipid peroxidation, decreased the mitochondrial membrane potential, and elevated the number of apoptotic cells in rat testes. Nano-quercetin ameliorated the testicular oxidative stress and apoptotic and endocrine parameters more efficiently than quercetin. Besides, nano-quercetin alleviated the histopathological and biochemical alterations of triazophos. It is concluded that nano-quercetin has higher anti-oxidant efficacy than quercetin in protecting rats against triazophos-induced testicular toxicity.

Negative correlations of mitochondrial DNA copy number in commercial frozen bull spermatozoa with the motility parameters after thawing

The purpose of the current study was to investigate the relationship between mitochondrial content of commercial frozen-thawed bull spermatozoa and motility. Firstly, mitochondrial DNA copy number per spermatozoon (MDCN), mitochondrial content (MC), the percentage of spermatozoa with high mitochondrial membrane potential (HMMP), intracellular reactive oxygen species (ROS) and motility parameters of frozen-thawed spermatozoa derived from five bulls were determined by using qPCR, flow cytometry and CASA, respectively, and analyzed the relationships. Results showed that all parameters examined, including MDCN, MC, HMMP, ROS and motility indicators, significantly differed among frozen spermatozoa from different bulls. Both MDCN and MC were negatively correlated with HMMP and motility indicators, but positively with ROS, of course, whereas there was a highly positive relationship between MDCN and MC. Secondly, when MDCN and MC were examined in frozen spermatozoa prepared at different points in the lives of four bulls, those did not correlate overall throughout their lives (1.3-14.3 years old), but did correlate significantly in two sires. From these results, we conclude that MDCN and MC of frozen spermatozoa differ among sires, and are negatively correlated with HMMP and sperm motility parameters, probably due to mitochondrial oxidative stress resulted in the presence of ROS, demonstrating that these appear to be useful markers to assess sires' spermatozoa. It should be noted that the MDCN and MC of bull spermatozoa may not vary overall with the age of the sire, whereas those changes with age in some individuals and may affect sperm motility.

The effects of purslane (Portulaca oleracea) and fennel (Foeniculum vulgare Mill) hydroalcoholic extracts on the functional parameters of human spermatozoa after vitrification

OBJECTIVE

Reactive oxygen species (ROS) are produced during cryopreservation of human sperm and impair sperm function. Antioxidant compounds, such as fennel and purslane, reduce the damaging effects of ROS. This study aimed to evaluate motility parameters, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), intracellular ROS, and DNA damage to determine the optimum concentrations of hydroalcoholic extracts of fennel and purslane for human spermatozoa cryopreservation.

METHODS

Twenty human sperm samples were used and divided into seven equal groups consisting of fennel hydroalcoholic extract (5, 10, and 15 mg/L), purslane hydroalcoholic extract (25, 50, and 100 mg/L), and no additive.

RESULTS

Supplementation of 25 mg/L and 50 mg/L purslane extract and 10 mg/L fennel extract in cryopreservation extender significantly increased the motility and PMI of sperm with a significant reduction in intracellular ROS compared to control groups (p<0.05). A 50 mg/L concentration of purslane extract elevated progressive motility and MMP compared to the control group (p<0.05). No significant differences were seen for motion patterns and DNA damage of frozen-thawed human sperm in extender containing these extracts.

CONCLUSION

The results showed that supplementation of 50 mg/L purslane extract and 10 mg/L fennel extract in semen cryopreservation extender has the potential to decrease intracellular ROS and subsequently elevate the motility and PMI of human sperm.

Animal board invited review: An update on the methods for semen quality evaluation in swine - from farm to the lab

Pig breeding is mainly conducted through artificial insemination with liquid-stored semen. It is, therefore, crucial to ensure that sperm quality is over the standard thresholds, as reduced sperm motility, morphology or plasma membrane integrity are associated with reduced farrowing rates and litter sizes. This work aims to summarise the methods utilised in farms and research laboratories to evaluate sperm quality in pigs. The conventional spermiogram consists in the assessment of sperm concentration, motility and morphology, which are the most estimated variables in farms. Yet, while the determination of these sperm parameters is enough for farms to prepare seminal doses, other tests, usually carried out in specialised laboratories, may be required when boar studs exhibit a decreased reproductive performance. These methods include the evaluation of functional sperm parameters, such as plasma membrane integrity and fluidity, intracellular levels of calcium and reactive oxygen species, mitochondrial activity, and acrosome integrity, using fluorescent probes and flow cytometry. Furthermore, sperm chromatin condensation and DNA integrity, despite not being routinely assessed, may also help determine the causes of reduced fertilising capacity. Sperm DNA integrity can be evaluated through direct (Comet, transferase deoxynucleotide nick end labelling (TUNEL) and its in situ nick variant) or indirect tests (Sperm Chromatin Structure Assay, Sperm Chromatin Dispersion Test), whereas chromatin condensation can be determined with Chromomycin A3. Considering the high degree of chromatin packaging in pig sperm, which only have protamine 1, growing evidence suggests that complete decondensation of that chromatin is needed before DNA fragmentation through TUNEL or Comet can be examined.

Effects of Antifreeze Protein Type I and Glycerol in Diluents on Cryopreserved Goat Epididymal Sperm

The effect of antifreeze protein (AFP) as a cryoprotectant used in different concentrations of glycerol on post-thaw quality of epididymal sperm was investigated. Sperm were isolated from 50 testicles, obtained from 25 healthy mature goat bucks, with progressive motility >80%, and total morphological abnormalities <10% were pooled in each replication. The semen samples were diluted with Tris-citrate-fructose-soybean lecithin extender containing different concentration of AFP [0 μg/mL (A0), 5 μg/mL (A5), 10 μg/mL (A10)]. Each concentration of AFP was added in an extender containing either 7% (G7) or 5% (G5) glycerol. Post-thaw total and progressive motility were found to be higher (p < 0.05) in groups A5G5 and A5G7. Plasma membrane integrity, sperm acrosome integrity, DNA integrity, acrosome intact sperm, and mitochondrial membrane potential were found to be higher (p < 0.05) in groups A5G5 and A10G5. Sperm viability was found to be higher (p < 0.05) in group A5G5, while lipid peroxidation was recorded lower (p < 0.05) in groups A5G5 and A5G7. Regarding the apoptosis occurrence, the results demonstrate higher (p < 0.05) live post-thawed spermatozoa for groups containing 5 μg/mL AFP with 5% and 7% glycerol in addition to the lowest (p < 0.05) value for groups containing 0 μg/mL AFP with 5% and 7% glycerol. Based on these results, the present study concludes that the addition of 5 μg/mL AFP in combination with 5% glycerol in freezing extender improves the post-thaw quality, structure, and function parameters for buck spermatozoa.

Almond and date fruits enhance antioxidant status and have erectogenic effect: Evidence from in vitro and in vivo studies

This study was designed to investigate the efficacies of almond and date fruits on redox imbalance and enzymes relevant to the pathogenesis of erectile dysfunction. The total polyphenol contents, ferric reducing antioxidant power, and vitamin C content were determined spectrophotometrically. Phenolic and amino acid compositions were quantified using HPLC; meanwhile, the antioxidant activities were determined using DPPH, ABTS, FRAP, and metal chelation. Also, the effect of almond and date extract on advanced glycated end-products (AGEs) formation, arginase, and phosphodiesterase-5 activities was evaluated in vitro. Thereafter, the influence of almond and date supplemented diets on copulatory behaviors in normal rats was assessed, followed by arginase and phosphodiesterase-5 activities determination in vivo. The results revealed that date and almond extracts exerted antioxidant properties, prevented AGEs formation in vitro, and inhibited arginase and phosphodiesterase-5 activities in vitro and in vivo. Besides, almond and date supplemented diets significantly enhance sexual behaviors in normal rats when compared with the control. Among the active compounds identified were gallic acid, ellagic acid, quercetin, and rutin. All the 20 basic amino acids were identified. Given the aforementioned, date and almond could represent a reliable source of functional foods highly rich in compounds with antioxidant activity, and arginase and PDE-5 inhibitory properties. PRACTICAL APPLICATIONS: Fruits are essential part of the human diet that furnish the body with important nutrients. Despite the crucial roles of fruits in human diets, some fruits like almond and date are underutilized among Nigerians. However, we characterized the important compounds present in these fruits and how their presence contributes to the biological activities of the fruits. Finally, we relate the chemical composition and the observed biological activities to the overall health and wellness of the consumers.

Advances in sperm cryopreservation in farm animals: Cattle, horse, pig and sheep

Sperm cryopreservation is one of the most important procedures in the development of biotechnologies for assisted reproduction. In some farm animals, the use of cryopreserved sperm has so many benefits for which relevance has become more evident in recent decades. Values for post-thaw sperm quality, however, are variable among species and within individuals of the same species. There is no standardized methodology for each of the stages of the cryopreservation procedure (andrological examination, semen collection, dilution, centrifugation, resuspension of the pellet with the freezing medium, packaging, freezing and post-thaw sperm evaluation), which also contributes to differences among studies. Cryotolerance markers of sperm and seminal plasma (SP) have been evaluated for prediction of ejaculate freezability. In addition, in previous research, there has been a focus on supplementing cryopreservation media with different substances, such as enzymatic and non-enzymatic antioxidants. In most studies, inclusion of these substances have led to improved post-thaw sperm quality and fertilizing capacity as a result of minimizing the adverse effects on sperm structure and function. Another approach is the use of different cryoprotectants. The aim with this review article is to provide an update on sperm cryopreservation in farm animals. The main detrimental effects of cryopreservation are described, including the negative repercussion on reproductive performance. Furthermore, the potential use of molecular biomarkers to predict sperm cryotolerance is discussed, as well as the addition of substances that can mitigate the harmful impact of freezing and thawing on sperm.

An evidence of Humanin-like peptide and Humanin mediated cryosurvival of spermatozoa in buffalo bulls

Buffalo spermatozoa are vulnerable to cryo-injuries due to inherent deficiency of endogenous antioxidants, high polyunsaturated fatty acids (PUFA) content in plasma membrane and low cholesterol/phospholipid (C/P) ratio. Humanin is a potent cytoprotective agent that protects the cells against oxidative stress and apoptosis. The present study was designed to establish the presence of Humanin in buffalo and effect of Humanin supplementation on freezability of buffalo spermatozoa. Indirect immunofluorescence test revealed presence of Humanin in ejaculated and epididymal spermatozoa, and, elongated spermatids and interstitial space in the testicular tissue section. Humanin levels in seminal plasma were significantly and positively correlated with sperm concentration and individual progressive motility (IPM) in good (n = 22; IPM >70%) and poor (n = 10; IPM <50%) quality ejaculates. For supplementation studies, a total of 24 ejaculates (IPM ≥70%) were collected and each ejaculate was then divided into four aliquots. First aliquot was diluted with egg yolk-tris-glycerol (EYTG) extender without Humanin and served as control group (Group I). Rest three aliquots were diluted with extender containing 2 (Group II), 5 (Group III) and 10 μM Humanin (Group IV), respectively. Semen was cryopreserved using standard protocol and evaluated at pre-freeze for lipid peroxidation (LPO) and post-thaw stages for spermatozoa kinematics, LPO, mitochondrial membrane potential (MMP), capacitation, apoptotic status and DNA integrity. The treatment group that showed best results (5 μM) was compared with control group for in vitro fertility assessment by homologous zona binding assay. The LPO levels were lower (p < 0.05) in 5 and 10 μM Humanin supplemented group. The MMP and DNA integrity were higher (p < 0.05) in 5 μM group than other groups. F-pattern was higher (p < 0.05) and B-pattern was lower (p < 0.05) in 5 and 10 μM Humanin supplemented groups. Lower apoptotic and higher viable spermatozoa (p < 0.05) were observed in 5 μM Humanin group. The mean number of spermatozoa bound to zona pellucida was higher (p < 0.05) in 5 μM Humanin treated group than the control group. The study established the presence of Humanin in buffalo spermatozoa and seminal plasma for very first time and concluded that Humanin supplementation at 5 μM concentration improves the freezability and in vitro fertility of buffalo spermatozoa.

Effect of Sperm Cryopreservation in Farm Animals Using Nanotechnology

Sperm cryopreservation is one of the sublime biotechnologies for assisted reproduction. In recent decades, there has been an increasing trend in the use of preserved semen. Post-thaw semen quality and values vary among animals of the same species. Similarly, there are species-specific variations in sperm morphology, i.e., sperm head, kinetic properties, plasma membrane integrity, and freezability. Similarly, the viability of sperm varies in the female reproductive tract, i.e., from a few hours (in cattle) to several days (in chicken). Various steps of sperm cryopreservation, i.e., male health examination, semen collection, dilution, semen centrifugation, pre- and post-thaw semen quality evaluation, lack standardized methodology, that result in differences in opinions. Assisted reproductive technologies (ART), including sperm preservation, are not applied to the same extent in commercial poultry species as in mammalian species for management and economic reasons. Sperm preservation requires a reduction in physiological metabolism by extending the viable duration of the gametes. Physiologically and morphologically, spermatozoa are unique in structure and function to deliver paternal DNA and activate oocytes after fertilization. Variations in semen and sperm composition account for better handling of semen, which can aid in improved fertility. This review aims to provide an update on sperm cryopreservation in farm animals.

Effect of aqueous Nigella sativa extract on the functional parameters of post-thaw human spermatozoa during vitrification

Objective

Sperm vitrification leads to the production of reactive oxygen species (ROS) that can damage the functional parameters of sperm. The present study aimed to investigate the antioxidant effect of Nigella sativa extract on motility, plasma membrane function, mitochondrial membrane potential (MMP), DNA damage, and intracellular ROS production.

Methods

A total of 20 sperm samples were used. Samples were divided into six experimental groups, including groups with aqueous extract from N. sativa seeds at concentrations of 1% to 6%, a cryopreserved control group, and a fresh control group.

Results

Statistical analysis showed significantly higher total sperm motility at concentrations of 3% to 6% than in the vitrified semen control group. Additionally, progressive motility and all motion characteristics at all concentrations were significantly higher than in the vitrified semen control group. The presence of N. sativa seed extract also improved the quality of the sperm parameters assayed in all experimental groups (1%–6%; intracellular ROS production, DNA damage, MMP, and sperm membrane function) compared to the control group.

Conclusion

Higher concentrations of N. sativa led to improvements in all sperm parameters and sperm quality. These findings indicate that N. sativa seed extract is effective for improving the quality of sperm after vitrification.

Aquaporins and Animal Gamete Cryopreservation: Advances and Future Challenges

Simple Summary

Cryopreservation is the method for the long-term preservation of gametes and embryos. In recent years, intensive research has focused on improving cryopreservation protocols for the determination of optimal freezing conditions and cryoprotective agents’ concentration for each cell type. The optimal cryopreservation protocol comprises the adequate balance between the freezing rate and the correct concentration of cryoprotective agents to achieve controlled cellular dehydration and minimal intracellular ice formation. Osmoregulation is, therefore, central in cryobiology. Water and some solutes can cross the plasma membrane, whereas facilitating transport takes a great part in intracellular/extracellular fluid homeostasis. Cells express water channels known as aquaporins that facilitate the transport of water and small uncharged solutes on their plasma membrane, including some cryoprotective agents. This review explores the expression and the function of aquaporins in gametes and embryos. In addition, the putative role of aquaporins for cryopreservation procedures is discussed.

Abstract

Cryopreservation is globally used as a method for long-term preservation, although freeze-thawing procedures may strongly impair the gamete function. The correct cryopreservation procedure is characterized by the balance between freezing rate and cryoprotective agents (CPAs), which minimizes cellular dehydration and intracellular ice formation. For this purpose, osmoregulation is a central process in cryopreservation. During cryopreservation, water and small solutes, including penetrating cryoprotective agents, cross the plasma membrane. Aquaporins (AQPs) constitute a family of channel proteins responsible for the transport of water, small solutes, and certain gases across biological membranes. Thirteen homologs of AQPs (AQP0-12) have been described. AQPs are widely distributed throughout the male and female reproductive systems, including the sperm and oocyte membrane. The composition of the male and female gamete membrane is of special interest for assisted reproductive techniques (ART), including cryopreservation. In this review, we detail the mechanisms involved in gamete cryopreservation, including the most used techniques and CPAs. In addition, the expression and function of AQPs in the male and female gametes are explored, highlighting the potential protective role of AQPs against damage induced during cryopreservation.

Cryoprotectant With A Mitochondrial Derived Peptide, Humanin, Improves Post-Thaw Quality Of Buffalo Spermatozoa

BACKGROUND: Semen cryopreservation results in deleterious effects on spermatozoa, including lipid peroxidation and a reduction in the total antioxidant components of seminal plasma. The ultimate outcome of these changes is a reduction in post-thaw semen quality. A mitochondrial derived peptide, humanin, a potent cytoprotective and antioxidant agent was used in the present study. OBJECTIVE: To evaluate the efficacy of a mitochondrial-derived peptide, humanin to improve the post-thaw quality of buffalo spermatozoa. MATERIALS AND METHODS: A total of 18 ejaculates from three Murrah buffalo bulls (n=6 each) were collected. Each ejaculate was divided into four aliquots. The first aliquot was diluted with standard EYTG dilutor (Group I, control), whereas the other three aliquots were diluted with EYTG supplemented with 2 μM (Group II), 5 μM (Group III) and 10 μM humanin (Group IV), respectively. Semen was evaluated for physico-morphological and functional attributes such as progressive motility, viability, abnormality, acrosome integrity, plasmamembrane integrity of fresh samples, pre-freeze and post-thaw stages. Oxidative stress parameters [lipid peroxidation (LPO) and total antioxidant capacity (TAC)] were also measured at the pre-freeze and post-thaw stages. RESULTS: Humanin s upplementation resulted in significantly higher (p≤0.05) post- thaw motility in all treatment groups and, higher (p≤0.05) viability in Groups III and IV in comparison to the control at the post-thaw stage. Spermatozoa with intact acrosome and plasma membran e were higher (p≤0.05) in Groups III and IV as compared to Group s I and II. The LPO levels at the post- thaw stage were found to be lower (p≤0.05) in all treatment groups versus the control group, whereas, higher (p≤0.05) TAC value s were recorded in Groups III and IV in comparison to the control and Group II. CONCLUSION: Humanin supplementation in the extender improved the freezabilty of buffalo spermatozoa.

Effect of Milk Type Subjected to Different Heat Treatments on Cryo-Survivability and In Vivo Fertility of Buffalo (Bubalus bubalis) Spermatozoa in a Milk-Based Extender

Oxidative stress is a major contributory factor to cellular damage during semen cryopreservation and results in a decreased fertilizing capacity of cryopreserved bull sperm. The inclusion of exogenous antioxidants sometimes exerts deleterious effects on sperm quality. Thus, enhancing the endogenous production of antioxidants is a requirement. This study aimed to investigate the effect of milk type heated at different temperatures on the antioxidant potential of extenders, and the subsequent post-thaw quality parameters and in vivo fertility of buffalo bull semen. Cow (C) and buffalo whole milk (B) were used separately for semen extender preparation, heated at five different temperatures (T₁ = 90°C, T₂ = 100°C, T₃ = 110°C, T₄ = 120°C, T₅ = 130°C) for 10 minutes. Reactive sulfhydryl groups were measured in each subgroup by Ellman's reagents as CT₁ = 143.2 μM, CT₂ = 147.4 μM, CT₃ = 151.5 μM, CT₄ = 157.2 μM, CT₅ = 161.8 μM, BT₁ = 168.3 μM, BT₂ = 172.5 μM, BT₃ = 176.7 μM, BT₄ = 196.3 μM, and BT₅ = 205.7 μM. All semen samples were cryopreserved in milk-based extenders by using standard procedures. Post-thaw quality parameters including total and progressive motility, mitochondrial membrane potential, plasma membrane integrity, and acrosome integrity were found to be higher (p < 0.05) in the group (BT₃) containing buffalo milk heated at 110°C, whereas in the same group, lipid peroxidation was found to be lower (p < 0.05) as compared with other treatment groups and control group. In vivo fertility of cryopreserved buffalo sperm was compared among BT₃, CT₁ (conventionally used milk extender), and a Tris egg yolk extender group. The fertility rates [47% (54/114), 30% (33/108), and 36% (37/103)] were higher (p < 0.05) in BT₃ as compared with other groups. This study suggests that buffalo milk heated at 110°C has high antioxidant potential and improves post-thaw quality and in vivo fertility of cryopreserved buffalo bull semen.

The antioxidant roles of L-carnitine and N-acetyl cysteine against oxidative stress on human sperm functional parameters during vitrification

Objective

Amino acids can protect sperm structure in cryopreservation due to their antioxidant properties. Therefore, the present study aimed to investigate the protective effect of L-carnitine (LC) and N-acetyl cysteine (NAC) on motility parameters, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), DNA damage, and human sperm intracellular reactive oxygen species (ROS) during vitrification.

Methods

Twenty normal human sperm samples were examined. Each sample was divided into six equal groups: LC (1 and 10 mM), NAC (5 and 10 mM), and cryopreserved and fresh control groups.

Results

The groups treated with LC and NAC showed favorable findings in terms of motility parameters, DNA damage, and MMP. Significantly higher levels of intracellular ROS were observed in all cryopreserved groups than in the fresh group (p≤0.05). The presence of LC and NAC at both concentrations caused an increase in PMI, MMP, and progressive motility parameters, as well as a significant reduction in intracellular ROS compared to the control group (p≤0.05). The concentrations of the amino acids did not show any significant effect.

Conclusion

LC and NAC are promising as potential additives in sperm cryopreservation.

Optimization of dissolved oxygen levels in extender prevents development of cryocapacitation like changes, oxidative stress and augments zona binding capacity of crossbred bull spermatozoa

The present study was undertaken to determine the efficacy of partial deoxygenation of extender at constant temperature (35°C) in freezability of crossbred bull semen. The dissolved oxygen (DO) levels were reduced by the use of newly developed technique of nitrogen effervescence at a flow rate of 2-3 bubbles per second. Four different levels of oxygen in semen extender, that is 11.7, 2, 4 and 8 ppm as control (Group-I), Group-II, Group-III and Group-IV, respectively, were used to assess the effect of partial deoxygenation on semen quality parameters. The 4 ppm level of DO resulted in higher (p < 0.05) progressive motility in comparison with non-treated group at post-thaw stage, whereas reduction up to 2 ppm resulted in drastic fall in motility. Oxidative stress status revealed low superoxide dismutase (SOD) and total antioxidant capacity (TAC) in Group-II, whereas higher (p < 0.05) SOD and TAC activities were observed in Group-III in comparison with non-treated group at pre-freeze and post-thaw stages. The sperm-zona binding at 4 ppm level of DO was significantly higher than control group, 2 and 8 ppm levels of DO. In conclusion, reduction of DO in the extender up to 4 ppm reduced oxidative stress and improved in vitro fertility of crossbred bull spermatozoa.

The Design of a New Catheter for Transcervical Artificial Insemination in Ewes

In ovine species, transcervical artificial insemination (TCAI) is limited by the poor quality of frozen-thawed semen and by the convoluted cervical lumen hampering the passage of inseminating devices. The aim of the study was to test the efficiency of three newly designed catheters with bent tips of 3.5 mm, 5.0 mm or 8.0 mm in terms of reproductive performances (experiment 1) and to compare the results of TCAI with the best performing catheter of experiment 1 to those obtained in ewes submitted to surgical incision of cervical folds (SICF) prior to insemination (experiment 2). The following parameters were assessed: time to pass the cervix; depth of cervical penetration; site of deposition of semen; pregnancy (PR); and lambing rates (LR). The results of experiment 1 indicated that the 5.0 mm tip catheter resulted in deeper and faster TCAI and higher PR and LR compared to 3.5 mm and 8.0 mm tip catheters (p < 0.05). In experiment 2, TCAI with the 5.0 mm catheter did not differ from TCAI after SICF in terms of depth of semen deposition, time to pass the cervix, PR and LR (p < 0.05). In conclusion, the use of a catheter that allowed transcervical uterine deposition of semen without excessive manipulation led to satisfactory pregnancy rates.

First successful frozen semen of the maned wolf (Chrysocyon brachyurus)

This study aimed to describe successful cryopreservation of sperm from maned wolves (Chrysocyon brachyurus). Three ejaculates from 2 maned wolves were collected by digital manipulation of the penis and evaluated subjectively, centrifuged and frozen in BotuCrio^® (Botupharma, Botucatu, Brazil) or Tris-yolk egg extender. Spermatozoa were thawed at 37ºC/30s or 70ºC/4s and evaluated for kinetics, morphology, plasma and acrosome membrane integrity, mitochondrial potential, hydrogen peroxide, superoxide anion and lipid peroxidation. From 5 thawed samples, two had sperm total motility >55% (56.0% and 64.0%) and progressive motility ~35% (35% and 40%), both frozen with Tris-yolk egg. Plasma and acrosome membrane integrity decreased and percentage of sperm defects increased post-thawing. We concluded that is possible to freeze spermatozoa from maned wolves using semen collection and processing methods applied for domestic dogs.

Dynamics of mitochondrial membrane potential and DNA damage during cryopreservation of cattle and buffalo bull spermatozoa

Understanding the changes in the spermatozoa during cryopreservation is indispensable for tailoring and increasing the efficiency of cryopreservation process success. However, the dynamics of damage to sperm organelles during different stages of cryopreservation is underexplored. This study assessed the mitochondrial membrane potential (MMP) and DNA damage during different stages of cryopreservation, viz. immediately after ejaculation, after equilibration and after freezing and thawing in cattle and buffalo spermatozoa using flow cytometry. Proportion of spermatozoa with high MMP decreased significantly after equilibration (from 66.06±4.59 to 42.58±6.30 in Holstein bulls and from 60.32±5.51 to 39.98±7.58 in buffalo bulls). Sperm DNA integrity [DNA fragmentation index (DFI %)] in Holstein Friesian (HF) bulls did not differ significantly between fresh and equilibrated samples but a significantly higher % DFI was observed in frozen-thawed semen samples as compared to both fresh and equilibrated samples. In contrast, % DFI in buffalo spermatozoa did not differ among the three stages of cryopreservation. It was concluded that mitochondrial damages occur during equilibration while chromatin damages occur during freezing and thawing of cattle bull spermatozoa; whereas buffalo bull spermatozoa were lesser susceptible to DNA damage during cryopreservation as compared to cattle spermatozoa.

Impact of Oxidative Stress on Male Reproduction in Domestic and Wild Animals

Oxidative stress occurs when the levels of reactive oxygen species (ROS) overcome the antioxidant defenses of the organism, jeopardizing several biological functions, including reproduction. In the male reproductive system, oxidative stress not only impairs sperm fertility but also compromises offspring health and survival, inducing oxidative damage to lipids, proteins and nucleic acids. Although a clear link between oxidative stress and male fertility disorders has been demonstrated in humans and laboratory rodents, little information is available about the implications of impaired redox homeostasis in the male fertility of domestic and wild animals. Therefore, this review aims to provide an update regarding the intrinsic and extrinsic factors that are associated with oxidative stress in the male reproductive system and their impact on the reproductive performance of domestic and wild animals. The most recent strategies for palliating the detrimental effects of oxidative stress on male fertility are reviewed together with their potential economic and ecological implications in the livestock industry and biodiversity conservation.

The effect of Quercetin on the quality of sperm parameters in frozen-thawed semen of patients with Asthenospermia

The study has aimed to investigate the effect of Quercetin, as a potent antioxidant, on preventing the negative effects of freezing process on sperm quality of patients with Asthenospermia. Semen sample from 25 patients was randomly divided into three groups; fresh, control and Quercetin (50 μM). Seven days after freezing, samples were thawed at ambient temperature. Total motility, progressive sperm motility, normal morphology, viability and DNA integrity were evaluated according to WHO criteria, Papanicolaou, eosin- nigrosine and acridine orange staining respectively. In addition, the health of sperm membrane and mitochondrial membrane potential was assessed by HOS test and rhodamine staining. MDA and antioxidant enzyme activity were also evaluated using ELISA method. In contrast to the fresh group, the mean level of MDA and DNA damage had significant increase in the control group and decreased significantly sperm quality (p ≤ 0.001). The mean percentage of total motility and progressive motility, normal morphology, viability and antioxidant enzyme activity had significant increase in the Quercetin group than the control group. In the Quercetin group, the MDA level and DNA damage also had significant reduction in comparison with the control group (p ≤ 0.001). Therefore, the Quercetin supplementation improves the quality of cryopreserved human semen.

Computational and Preclinical Evidence of Anti-ischemic Properties of L-Carnitine-Rich Supplement via Stimulation of Anti-inflammatory and Antioxidant Events in Testicular Torsed Rats

Ischemia-reperfusion injury is a urological emergency condition that could lead to necrosis, testicular damage subfertility, and infertility. The purpose of this study was to identify changes taking place in the rat testis at short-term (4 hr) as well as long-term (7 days) reperfusion following testicular torsion and to evaluate the effects of Proxeed Plus (PP), L-carnitine-rich antioxidant supplement, on preventing these changes using the biochemical parameters and histopathology. Thirty adult male rats were divided into five groups: in groups, 1-4 testicular ischemia was achieved by rotating the left testis 720° clockwise for 4 h and dividing into the sham, torsion/detorsion (T/D), T/D+1000 mg/kg BW PP, and T/D+5000 mg/kg BW PP groups, respectively. PP was administered intraperitoneally 30 min before detorsion while group 5 served as the normal control. All rats were sacrificed 4 h after detorsion. The same experimental design was set up, and animals were sacrificed after 7 days of detorsion. The testicular levels of human cyclooxygenase-2; tumor necrosis factor; interleukins-1β, 6, and 10; hydrogen peroxide; malonaldehyde; superoxide dismutase; catalase; glutathione transferase; glutathione peroxidase; glutathione reductase; and histopathological damage were evaluated. Our results revealed that rats in the torsion/detorsion group exhibited elevated testicular levels of oxidative markers and proinflammatory cytokines, low levels of antioxidant enzymes, and severe histological alterations relative to the control and sham groups. Treatments with 1000 and 5000 mg/kg BW of PP for 4 hr and 7 days significantly (p < 0.05) decreased the levels of the proinflammatory and oxidative markers while increasing the spermatogenesis, testicular levels of antioxidant enzymes, and anti-inflammatory cytokine (IL-10) in a dose-dependent manner. This suggested that PP exhibited anti-inflammatory and antioxidant activities against I/R testes thus serving as an effective supplement to protect against testicular assault.

Toxicity assessment of chronic exposure to common insecticides and bee medications on colony development and drones sperm parameters

The effect of agrochemicals and beekeeping treatments on drones have not been widely investigated compared to workers or queens. In the present study, we investigated the chronic exposure of chemicals set (deltamethrin, acetamiprid, oxalic acid, fumagillin, and amitraz) on some sperm parameters and on the histomorphology of seminal vesicles. We also assessed the colony development and nosema load before and after the exposure. Thirty native Apis mellifera anatolica honeybee colonies with sister queens equalized with brood and total frame of bees were used for this experiment. Five colonies were used for each group. Deltamethrin, acetamiprid and fumagillin were given as oral chronic exposure at final concentrations of 25.10^-6 mg L^-1, 0.01 m L^-1 and 50 mg L^-1 respectively in syrup solution (50/50). Colonies were exposed to oxalic acid by spraying 5 mL per frame space of 3% (w/v) of oxalic acid dihydrate. Finally, the amitraz was applied based on the manufacturer's instructions. The concentrations chosen represented the field-realistic concentrations and those used by beekeepers in the region. Results showed that deltamethrin reduced brood production. In the same group, we found a high increase in nosema load. All treatments decreased sperm count except for fumagillin but this compound increased sperm mortality and increased the percentage of sperm with defected acrosome integrity. The amitraz exhibited a high sperm mortality and high percentage of sperm with defected membrane integrity function. The sperm parameters such as the count, the motility, the acrosome integrity, the membrane function of sperm, and the histomorphology of seminal vesicles of drones exposed to oxalic acid were the most affected. Bee medications commonly used such as oxalic acid and fumagillin should be more investigated and should be considered by beekeepers and particularly queen breeders.

Improving the quality and in vitro fertilization rate of frozen-thawed semen of buffalo (Bubalus bubalis) bulls with the inclusion of vitamin B12 in the cryopreservation medium

This study was designed to evaluate the effects of vitamin B₁₂ in cryopreservation medium on frozen-thawed semen of buffalo (Bubalus Bubalis) bulls. Semen from five bulls (fertility-proven) were diluted in five aliquots not supplemented (control), or supplemented with 1, 2, 4, or 5 mg/mL of vitamin B₁₂ and evaluated using the Computer Assisted Sperm motion Analysis, antioxidant enzymes, lipid peroxidation (LPO), reactive oxygen species (ROS), ATP concentrations, and in vitro fertilization rate (%). Sperm progressive motility, rapid velocity (%), mitochondrial potential, and acrosome integrity were greater (P < 0.05) with supplementation of 4, and 5 mg/mL vitamin B₁₂ than the control sample. Similarly, compared with the control, samples with 5 mg/mL vitamin B₁₂ supplementation had markedly greater average-path, straight-line, and curved-line velocities (μm/sec). Semen samples supplemented with 2, 4 and 5 mg/mL vitamin B₁₂ had greater concentrations of GPx (U/mL) and SOD (U/mL), whereas LPO (μM/mL) was less (P < 0.05) compared with the control sample. Seminal plasma ROS concentrations (10⁴/25 × 10⁶) were less in the 5 mg/mL vitamin B₁₂ supplemented than control sample. Semen samples supplemented with 5 mg/mL of vitamin B₁₂ had greater concentrations of ATP than control and the 1 mg/mL vitamin B₁₂ supplemented sample. Semen samples supplemented with 5 mg/mL of vitamin B₁₂ had greater plasmalemma and DNA integrities (%) than the control sample. In summary, vitamin B₁₂ supplementation augments semen quality, as evidenced by values for CASA variables, antioxidant enzymes, and ATP concentrations, which may occur as a consequence of inhibition in LPO and ROS production by buffalo spermatozoa.

Effects of Selenium on Bull’s Sperm Oxidative Stress and Viability Under in Vitro Conditions

The aim of this study was to determine the effects of sodium selenite on the level of oxidative stress and viability of spermatozoa in fresh bull ejaculate in in vitro conditions at different temperatures. Samples of the bull's ejaculates with a concentration of 7 × 105 spermatozoa per ml were placed into the commercial semen extender containing 0 (control), 1 (1Se), 3 (3Se) and 5 (5Se) µg.ml–1 of sodium selenite. The following analyses were performed by flow cytometry after 1, 3, 6, 8, 24, 48 and 72 hours of incubation at 4 °C and 37 °C. All analyses were carried out in triplicate. The level of oxidative stress at both temperatures were significantly lower in the experimental groups in comparison to the control group. However, a significant decline of live sperm concentration and a rise of damaged sperm concentration were recorded, especially in groups 1Se and 3Se in comparison to the control group. Only in group 5Se was there observed a positive effect on the damaged spermatozoa level in comparison with groups C, 1Se and 3Se at 4 °C. In conclusion, the applied concentrations of sodium selenite had a positive effect on the level of oxidative stress in all experimental groups, but mainly at concentration of 5 µg.ml–1 of sodium selenite, especially at 4 °C. However, the effect of selenium was not sufficient for improving the sperm viability.

Lipid peroxidation in bull semen influences sperm traits and oxidative potential of Percoll®-selected sperm

Although bovine embryo in vitro production (IVP) is a common assisted reproductive technology, critical points warrant further study, including sperm traits and oxidative status of sperm for in vitro fertilization (IVF). Our aim was to evaluate whether the lipid peroxidation index of commercial bull semen is influenced by sperm traits and oxidative status of sperm populations selected using Percoll® gradient. Semen straws from 48 batches from 14 Nelore bulls were thawed individually, analyzed for motility and subjected to Percoll selection. After Percoll, the lipid peroxidation index of the extender was evaluated, whereas selected sperm were analyzed for motility, acrosome and membrane integrity, mitochondrial membrane potential, chromatin resistance and oxidative potential under IVF conditions. Batches were divided retrospectively in four groups according to lipid peroxidation index. Sperm from Group 4 with the lowest index of lipid peroxidation had, after Percoll selection, greater plasma membrane integrity (81.3%; P = 0.004), higher mitochondrial potential (81.1%; P = 0.009) and lower oxidative potential (135.3 ng thiobarbituric acid reactive substances (TBARS)/ml; P = 0.026) compared with Group 1 with highest lipid peroxidation index (74.3%, 73% and 213.1 ng TBARS/ml, respectively). Furthermore, we observed negative correlations for the lipid peroxidation index with motility, membrane integrity and mitochondrial potential, and positive correlations with oxidative potential. In conclusion, oxidative stress in semen straws, as determined using lipid peroxidation in the extender, is associated with sperm traits and their oxidative potential under IVF conditions. These results provided further insights regarding the importance of preventing oxidative stress during semen handling and cryopreservation, as this could affect sperm selected for IVF. Finally, Percoll selection did not completely remove sperm with oxidative markers.

Effect of sulforaphane on apoptosis, reactive oxygen species and lipids peroxidation of human sperm during cryopreservation

Sperm cryopreservation is a common procedure to preserve viable sperm for an indefinite period. This procedure has numerous detrimental effects on sperm function due to increased generation of reactive oxygen species (ROS). During cryopreservation, while ROS increases, antioxidant enzymes level decreases. It has been shown that a relationship exist between lower antioxidant levels and infertility. l-Sulforaphane (SFN) is an isothiocyanate in cruciferous vegetables of the brassica class that has potent protective effects against oxidative stress. The purpose of the present study was to evaluate the effects of SFN supplementation during the freeze-thaw process on different parameters of human spermatozoa which can influence sperm fertilizing ability. Samples were collected from 25 healthy men and each sample was divided into three groups: fresh, control (untreated frozen/thawed samples) and treatment (treated frozen/thawed with SFN) groups. Sperm parameters, ROS production (using flow cytometry), plasma membrane integrity (using flow cytometry), Lipid peroxidation (using ELISA) were evaluated. Our results demonstrated that 5 μM SFN improved all parameters of sperm including viability (P < 0.001), motility, and morphology (P < 0.05) after the freeze-thaw process. Furthermore, SFN reduced the levels of intracellular hydrogen peroxide (P < 0.01) and superoxide anion (P < 0.05). Also, SFN significantly increased the percentage of viable sperm cells with the intact plasma membrane (P < 0.001) and decreased the level of lipid peroxidation after the freeze-thaw process (P < 0.01).Our findings showed that spermatozoa treatment with 5 μM SFN before the freeze-thaw process has protective effects against oxidative stress and could decrease the detrimental effects of this process on sperm quality.

The effect of cysteine and glutamine on human sperm functional parameters during vitrification

Assuming the adverse effects of reactive oxygen species (ROS) on sperm function, this study was conducted to assess the effects of cysteine and glutamine as effective antioxidants on human sperm parameters under vitrification. Twenty normozoospermic samples were used. The samples were subjected to a vitrification process and cysteine (5 and 10 mM) and glutamine (10 and 15 mM). The sperm motility parameters, mitochondrial membrane potential (MMP), plasma membrane integrity (PMI), DNA damage and intracellular ROS damage were assessed for each sample. Statistical analyses showed that motility, mitochondrial membrane potential and DNA damage decreased in the vitrified groups with cysteine 5, 10 mM and glutamine 10, 15 mM separately. Also intracellular ROS increased significantly compared to the fresh group (p < .05). No significant differences were observed for PMI compared with the fresh group (p > .05). Supplementation of cysteine and glutamine in both concentrations separately decreased intracellular ROS and DNA damage of spermatozoa with significant increase in PMI, MMP and progressive motility compared to vitrified control group (p < .05). The results showed no significant effect of a specific concentration in cysteine and glutamine on sperm parameters compared to other concentrations. Both amino acids have the potential to improve the harmful effects of freezing on sperm parameters.

Low-density lipoproteins protect sperm during cryopreservation in buffalo: Unraveling mechanism of action

This study was carried out to reveal factors and the mechanism of action by which low-density lipoproteins (LDLs) protect sperm better than egg yolk (EY) during cryopreservation. We extracted LDL from EY and compared the amount of calcium, progesterone, and antioxidants in EY and LDL. We found a very high concentration of progesterone (1423.95 vs. 10.46 ng/ml) and calcium (29.19 vs. 0.47 mM) in EY as compared with LDL. Antioxidant assays like DPPH (2,2-diphenyl-1-picrylhydrazyl) and the ferric reducing antioxidants power assay revealed that the LDL extender had almost double ability to lose hydrogen than the EY extender. For sperm cryopreservation, 20 ejaculates from four Murrah buffalo bulls were collected. Each ejaculate was divided into four aliquots and extended in 10%, 12%, and 14% LDL (w/v) and EY-based extenders, followed by cryopreservation. The LDL-based extender prevented excessive cholesterol efflux, and its high content of antioxidants minimized reactive oxygen species generated during cryopreservation, resulting in a functional CatSper channel. The EY-based extender promoted excess cholesterol efflux due to the presence of high-density lipoprotein, resulting in a compromised CatSper channel. High intracellular calcium in a cryopreserved sperm in the EY group as compared with the LDL group indicates that progesterone present in EY activates the CatSper channel, resulting in a heavy calcium influx into the sperm. The greater tyrosine phosphorylation and increased number of F-pattern in the sperm cryopreserved in the EY extender indicate that high intracellular calcium triggers more capacitation-like changes in the sperm cryopreserved in EY than LDL extender. In conclusion, we demonstrated the new facts and understandings about LDL and EY for semen cryopreservation.

Effect of Cooling and Freezing on Llama (Lama glama) Sperm Ultrastructure

Semen cryopreservation in South American camelids has a low efficiency. Post-thaw viability of sperm is low, and poor results are obtained when artificial insemination is performed with cryopreserved semen, impeding advances both in accelerated genetic progress and selection. This study aimed to describe the effect of a conventional method of camelid semen cryopreservation on the llama sperm ultrastructure during cooling and freezing, using transmission and scanning electron microscopy (TEM, SEM). Sperm motility, vigor, viability, and DNA integrity during those steps were also examined. Ejaculates from five fertile adult llama males were obtained by electroejaculation. For cooling, semen samples were washed with Hepes-balanced salt solution (HBSS), diluted in Tris-citric acid-fructose egg yolk extender (TCF-EY), and then cooled until 5°C for 24 h. For freezing, sperm samples were washed with HBSS, diluted in TCF-EY and cooled until 5°C for 2.5 h. Samples were equilibrated with TCF-EY, supplemented with 6% glycerol at 5°C for 20 min, and then stored in liquid nitrogen for a month before thawing. TEM and SEM analyses were carried out on sperm samples prior to cryopreservation, after cooling down until 5°C for 2.5 and 24 h, and after the freeze-thaw process. Ultrastructural injury was noticed during cooling, even though sperm motility, vigor, viability, and DNA integrity were not significantly affected. Analysis revealed plasma membrane and acrosome damage, loss of mitochondria, and axoneme and periaxonemal structure disorganization after 2.5 h of cooling. During freezing, a significant decrease in sperm motility and viability was observed after thawing. TEM and SEM revealed prominent signs of post-thawing damage. The plasma membrane was lost or exhibited various degrees of swelling, undulation, and perforations. Besides, the sperm presented vacuoles in the nucleus and broken acrosomes. Mitochondria in the midpiece showed vacuolization and structural disorganization. In conclusion, SEM and TEM revealed that cryopreservation induced ultrastructural damages in llama sperm that initiated during cooling and intensified during freezing. These details provide valuable data for further studies to minimize cryodamage in camelid sperm.

Epigallocatechin-3-gallate (EGCG) addition as an antioxidant in a cryo-diluent media improves microscopic parameters, and fertility potential, and alleviates oxidative stress parameters of buffalo spermatozoa

The disparity between the endogenous antioxidants concentration and free radicals in spermatozoa results in reactive oxygen species (ROS) generation. In this prospect, epigallocatechin-3-gallate (EGCG) preserves vigorous antioxidant features. Current study explored the influence of EGCG in a cryo-diluent media on microscopic parameters, oxidative stress parameters, and fertility potential of buffalo spermatozoa during cryopreservation. Concisely, collected semen from three donor bulls for four times were then evaluated for volume, motility, concentrations and then dilution in a cryo-diluent media with different concentrations of EGCG (EGCG-0 = control; EGCG-50 = 50 μM, EGCG-100 = 100 μM, EGCG-200 = 200 μM, and EGCG-300 = 300 μM) at 37 °C, cooled to 4 °C in 2 h, equilibrated for 4 h at 4 °C, and cryopreserved. At post-thawing, Computer-Assisted Sperm motion Analysis motilities (total and progressive, %) and rapid velocity (%), plasma membrane functionality, supravital plasma membrane integrity, and mitochondrial potential (%) were found higher (P < 0.05) in EGCG-200, and EGCG-300 than control, whereas average-path, straight-line, and curved-linear velocities (μm/sec), and acrosome integrity (%) were recorded higher in EGCG-300 than control. Further, comet length (μm), and tail length (μm), LPO (lipid peroxidation, μM/mL), and apoptosis-like changes (%) in spermatozoa were significantly decreased in EGCG-300 than control. Seminal plasma antioxidant enzymes activities (glutathione peroxidase, U/mL, and superoxide dismutase, U/mL) were increased with EGCG-300 than control. Moreover, EGCG-300 addition in a cryo-diluent media improves the fertility potential (%) of buffalo spermatozoa. In a nutshell, the inclusion of EGCG-300 in a cryo-diluent media enhances post-thaw microscopic parameters, and fertility potential, whereas decreases oxidative stress parameters in buffalo spermatozoa.

The role of environmental optimization for storing bulls' sperm cells

Artificial insemination has achieved a dynamic increase in genetic progress, and this is due to the improvement of sperm preservation technology. In recent years, a lot of attention has been paid to optimizing bull sperm storage environment and objectifying methods of sperm quality analysis. This review presents bull sperm preservation methods and ways to modify their storage environment. The main purpose of sperm preparation for artificial insemination is to obtain sperm with a high percentage of viable, motile sperm with normal morphology and low DNA fragmentation rates. Currently conducted experiments indicate the possibility of improving the quality of insemination doses produced using various components enriching common diluents. However, despite extensive research, no better results have been achieved than obtaining insemination doses with sperm viability that exceeds just over 60%. Obtaining a very good quality of frozen semen seems to be still unachievable today.

Escherichia coli membrane-derived oxygen-reducing enzyme system (Oxyrase) protects bubaline spermatozoa during cryopreservation

The objective of this study was to determine the effectiveness of deoxygenation of semen extender using Escherichia coli membrane-derived oxygen scavenger (Oxyrase) on post-thaw quality of buffalo (Bubalus bubalis) spermatozoa. Sixteen semen ejaculates, four each from four bulls, were each divided into five equal fractions, diluted using Tris-egg yolk extender supplemented with different concentrations of Oxyrase (0, 0.3, 0.6, 0.9, and 1.2 U/ml), designated as treatments T1, T2, T3, T4, and T5, respectively, and cryopreserved. Immediately after thawing, Oxyrase did not improve sperm kinetics and motility; however, it improved the keeping quality (significantly lower deterioration of post-thaw sperm motility after incubation for 120 min) in T3. Further, T3 reduced (p < .05) cholesterol efflux and protected the intactness of the sperm plasma membrane. Flow cytometry with Fluo-3 AM/propidium iodide (PI) dual staining revealed the highest (p < .05) proportion of live spermatozoa with low intracellular calcium in T3. Oxyrase supplementation protected spermatozoa from premature capacitation which was confirmed by low expression of tyrosine-phosphorylated proteins (32, 75, and 80 kDa) and a relatively lower percentage of F-pattern (uncapacitated spermatozoa) in chlortetracycline assay. Importantly, the Oxyrase fortification decreased superoxide anion in a dose-dependent manner indicating reduced availability of oxygen at sperm mitochondrial level. Similarly, in Oxyrase-fortified sperm, malondialdehyde concentration, an index of lipid peroxidation, is also reduced in a dose-dependent manner. In conclusion, we demonstrate that deoxygenation of buffalo semen by Oxyrase has the potential of improving post-thaw sperm quality by overcoming the problem of cryocapacitation and oxidative damage during cryopreservation process.

Alpha-tocopherol improves sperm quality by regulate intracellular Ca2+ intensity (influx/efflux) of Simmental bull cattle sperm

Background

The effects of α-tocopherol on intracellular Ca²⁺ intensity in semen cryopreservation by regulate intracellular Ca²⁺ intensity have not been reported yet.

Objective

The research was conducted to evaluate the effect of supplementation α- tocopherol into egg yolk skim milk extender on sperm quality and intracellular Ca²⁺ intensity.

Methods

Semen samples were collected and supplemented with respectively 0mM (P0); 0.5mM (P1); 1mM (P2); 1.5mM (P3) and 2mM (P4) α-tocopherol in extender before cryopreservation processes. Post-thawing sperm was evaluated for motility, viability, and abnormality using Phase Contrast Microscope (200x) with eosin-nigrosine staining, and intracellular Ca²⁺ intensity of the best result dose was evaluated using Confocal Laser Scan Microscope (400x) with Fluo-3 Staining.

Results

The results showed there was a significant difference (P≤0.05) in sperm motility and viability between P0; P1 with P2; P3; P4. The Motility and viability between groups P0; P1 and P3; P4 showed no significant difference (P≥0.05), while P2 with P3; P4 showed significant difference (P≤0.05). There was a significant difference (P≤0.05) in sperm abnormality of P0; P1 with P2; P3; P4. The abnormality between P0; P1 and P2; P3 showed no significant difference (P≥0.05), while P2; P3 showed a significant difference with P4 (P≤0.05). The best result in sperm quality was supplementation with 1.5mM α-tocopherol. Ca²⁺ intracellular intensity: 142.76± 21.8 au (P0) and 176.06±61.43 au (P3).

Conclusions

It was concluded that 1.5mM α-tocopherol is the best dose to improve sperm quality by regulating intracellular Ca²⁺ intensity on Simmental bull cattle.

Caffeic acid improves microscopic sperm parameters and antioxidant status of buffalo (Bubalus bubalis) bull semen following freeze-thawing process

This study investigates the effects of cryopreservation and supplementation of buffalo's semen with Caffeic acid. It studies the effects of different Caffeic acid concentrations on cryopreservation capacity of the buffalo and evaluates their influence on various sperm parameters like motility, viability, progressive motility, sperm plasma membrane integrity, and antioxidant status. Twenty-four semen samples were collected with an artificial vaginal from three adult water buffalos. The semen samples were evaluated and the qualified ejaculates were separated and were diluted in a Tris-based extender. The resulting samples were classified into 5 groups: No antioxidant (control), Control sham (NaOH), Caffeic acid 50 μM, Caffeic acid 100 μM, and Caffeic acid 200 μM. The semen samples encountered cryodamage and the quality was deteriorating during the cryopreservation (P < 0.05). The semen evaluation after thawing showed that the groups of samples receiving 100 μM Caffeic acid had higher viability, total motility, and lower abnormal sperm and better linearity (LIN), curvilinear velocity (VCL), straight-line velocity (VSL) and path velocity and higher intact plasma membrane (P < 0.05) compared to other groups. It is notable that adding 100 μM Caffeic acid to freezing extenders enhances the CAT, GPx, SOD, and GSH and also ameliorates total antioxidant capacity of spermatozoa after thawing. It is notable that the addition of 100 μM Caffeic acid decreases the amount of Malondialdehyde. These reactions lead us to conclude that 100 μM Caffeic acid enhances the semen quality of water buffalo after thawing.

Nano-purification of raw semen minimises oxidative stress with improvement in post-thaw quality of buffalo spermatozoa

The study consisted of application of anti-ubiquitin antibodies (Abs)-coated iron oxide-nanoparticles (IONPs) for minimisation of oxidative stress to contemporary live spermatozoa from the raw semen. Round-shaped IONPs (12.09 ± 0.91 nm) after two-stage functionalisation (silanisation and pegylation) were conjugated with Abs. Four aliquots from each of the 24 ejaculates (4 buffalo bulls) formed Control (Group I) and treatment (II, III and IV) groups; each containing 150 ± 25 million dead/damaged spermatozoa. IONPs-Abs complex were added at ratio of 1:1 (0.5 µg/ml), 1:2 (1.0 µg/ml) and 1:4 (2.0 µg/ml), respectively, in Groups II, III and IV. The semen quality parameters showed improvement at lag-stage (post-nano-purification before processing for cryopreservation). The mean post-thaw motility (%) in Group IV was found to be greater (p < .05) than Group I. Moreover, the overall DNA integrity (%) at post-thaw stage was improved in the nano-purified semen samples. The value of malondialdehyde was greater (p < .001) in Group I than Groups II, III and IV. The mean total antioxidant capacity and superoxide dismutase (U/mg protein) activity values in Group IV was greater (p < .05) than Group I. The study results show that IONPs conjugated with anti-ubiquitin Abs at 2.0 µg/ml can be an effective dose for depletion of dead/damaged spermatozoa from buffalo ejaculates to minimise oxidative stress.

The addition of resveratrol in tris citric acid extender ameliorates post-thaw quality parameters, antioxidant enzymes levels, and fertilizing capability of buffalo (Bubalus bubalis) bull spermatozoa

Resveratrol is a natural grape-derived polyphenol with potent antioxidant properties that protect spermatozoa against lipid peroxidation (LPO) by eradicating free radicals. The objectives of this study were to 1) appraise the effects of resveratrol in extender on post-thaw quality parameters, antioxidant enzymes, adenosine triphosphate (ATP), DNA fragmentation, LPO and 2) fertilizing capability of buffalo bull spermatozoa. Semen was collected from four fertility proven bulls with artificial vagina thrice, evaluated initially, and diluted in five different extenders containing resveratrol (T4 = 100 μM, T3 = 50 μM, T2 = 20 μM, T1 = 10 μM), and control (no resveratrol), and evaluated after post-dilution and post-thawing stage of cryopreservation. Analysis of variance revealed that, there was no difference (P > 0.05) in any parameters due to treatments at post-dilution. However, at post-thawing, sperm progressive motility (%), plasma membrane integrity (%), mitochondrial membrane potential (%) and ATP levels (nmol/10⁶) were found higher in semen samples cryopreserved in T3 and 4 than control. Sperm supravital plasma membrane integrity (%) and viable/acrosome integrity were found higher in semen samples cryopreserved in T4 than control and T1. Furthermore, sperm catalase (U/mL), glutathione peroxidase (μM) and superoxide dismutase (U/mL) concentrations were found significantly higher in resveratrol treated groups as compared to the control. Conversely, DNA fragmentation (%) and LPO (μM/mL) were significantly (P > 0.05) decreased in semen samples cryopreserved in T4 in comparison to the control. Fertilizing capability was found higher in semen samples cryopreserved in T4 as compared to the control (%, 77.33 vs. 57.41, P < 0.05). It is concluded that the addition of resveratrol in extender ameliorates quality parameters, antioxidant enzymes levels and fertilizing capability, and alleviate DNA fragmentation and LPO in buffalo spermatozoa during cryopreservation.

Sperm Cryodamage in Ruminants: Understanding the Molecular Changes Induced by the Cryopreservation Process to Optimize Sperm Quality

Sperm cryopreservation represents a powerful tool for livestock breeding. Several efforts have been made to improve the efficiency of sperm cryopreservation in different ruminant species. However, a significant amount of sperm still suffers considerable cryodamage, which may affect sperm quality and fertility. Recently, the use of different “omics” technologies in sperm cryobiology, especially proteomics studies, has led to a better understanding of the molecular modifications induced by sperm cryopreservation, facilitating the identification of different freezability biomarkers and certain proteins that can be added before cryopreservation to enhance sperm cryosurvival. This review provides an updated overview of the molecular mechanisms involved in sperm cryodamage, which are in part responsible for the structural, functional and fertility changes observed in frozen–thawed ruminant sperm. Moreover, the molecular basis of those factors that can affect the sperm freezing resilience of different ruminant species is also discussed as well as the molecular aspects of those novel strategies that have been developed to reduce sperm cryodamage, including new cryoprotectants, antioxidants, proteins, nanoparticles and vitrification.

The effect of crude guava leaf tannins on motility, viability, and intact plasma membrane of stored spermatozoa of Etawa crossbred goats

Aim

The aim of this study was to know crude guava leaf tannins effect on motility, viability, and intact plasma membrane of stored spermatozoa of Etawa crossbred goats.

Materials and Methods

Macroscopic assessment of normal Etawa crossbred semen was followed by dilution with a glucose solution at a 1:10 ratio to increase volume. The diluted semen was treated by adding crude guava leaf tannins into 1 ml of the semen glucose diluent, and five treatments were obtained, namely, control group (C), with no added tannins; treatment Group 1 (T1), with 3%; treatment Group 2 (T2), with 6% tannins; treatment Group 3 (T3), with 12% tannins; and treatment Group 4 (T4), with 24% tannins. Each treatment used five replications. Then, microscopic analysis of the treated and control semen was carried out after 15 days of storage at 4-5°C temperature. The parameters observed were motility, pH, viability, abnormality, and intact spermatozoa plasma membrane.

Results

The spermatozoa motility in Group C was the highest (76.60±1.47). The motility in Group T1 did not differ from that in Group C, but was different and higher than that in Groups T2, T3, and T4. The pH of Group C tended to be acidic after 15 days of storage (4.78±0.01) as compared to the initial pH of fresh semen (6.76±0.12). The pH in Group C did not differ from that in the Groups T1 and T2, but differed from that in the T3 and T4 groups; the pH in the T3 and T4 groups was similar. The viability of spermatozoa in the T1 group was higher than that in all treatments (64.60±2.76); the lowest values were found in Group C (28.94±1.02). Group C had the lowest number of normal spermatozoa, with a mean of 72.58±3.48. The total number of abnormalities in the T2 group did not differ from those in the T3 group, and abnormalities in the T4 group did not differ from those in Group C, which exhibited the highest abnormalities in the head, neck, and tail. The most significant decrease was observed in the intact plasma membrane of spermatozoa on addition of 12% and 24% crude guava leaf tannin in glucose diluents.

Conclusion

The addition of 3% crude guava leaf tannin to crossbred Etawa goat semen diluted with glucose diluent and stored for 15 days at 4-5°C resulted in a significant effect on spermatozoa motility, viability, and intact plasma membrane, whereas the administration of 24% crude guava leaf tannin resulted in low live percentage of spermatozoa.

Effect of carboxylated poly l-Lysine as a cryoprotectant on post-thaw quality and in vivo fertility of Nili Ravi buffalo (Bubalus bubalis) bull semen

Buffalo bull sperm are more prone to cryo-injuries. Glycerol being the most common permeable cryoprotectant exerts cytotoxic effects on sperm which cause a reduction in fertility. Thus, the exploration of new cryoprotectant is needed. For this purpose, we investigated the effect of carboxylated poly l-Lysine (CPLL) as cryoprotectant used with different concentrations of glycerol on post-thaw sperm motility, kinematics, plasma membrane integrity, mitochondrial membrane potential (MMP), lipid peroxidation (LPO), catalase concentration and in vivo fertility of Nili Ravi buffalo bull semen. In experiment 1, semen samples (n = 15, bulls = 3) were diluted with Tris-citrate-egg yolk extender containing different concentration of CPLL [0% (C0), 0.25% (C0.25), 0.5% (C0.5), 0.75% (C0.75), 1% (C1)]. Each concentration of CPLL was added in extender containing either 7% (G7) or 5% (G5) glycerol. Diluted semen samples were cooled and cryopreserved using standard procedures. Post-thaw total and progressive motility, plasma membrane integrity, acrosome integrity, and MMP were found higher (P < 0.05) in group (G5C0.75) containing 0.75% CPLL and 5% glycerol as compared to the control group (G7C0) and other groups while LPO was recorded lower (P < 0.05) in the same group (G5C0.75). In experiment 2, in vivo fertility was compared between G5C0.75 (5% Glycerol+ 0.75% CPLL; depicted better post-thaw quality) and control group G7C0. Buffaloes were inseminated after 24 h of onset of estrus. Pregnancy diagnosis was performed per rectum at least 60 days post insemination. The fertility rates [56% (58/102) vs. 36% (37/103)] were higher (P < 0.05) in G5C0.75 as compared to the control group G7C0. Based upon these results, this study concludes that the addition of 0.75% CPLL in combination with 5% glycerol in freezing extender improves the post-thaw structure, function and in vivo fertility of Nili Ravi buffalo bull semen.