Addition of Antioxidants Myoinositol, Ferulic Acid, and Melatonin and Their Effects on Sperm Motility, Membrane Integrity, and Reactive Oxygen Species Production in Cooled Equine Semen

Effects of apigenin and trans-ferulic acid on microscopic and oxidative stress parameters in the semen of water buffalo bulls during cryopreservation

Cryopreservation involves exposing sperm to stressful conditions that affect cell viability. The high quality of the Azerbaijani water buffalo's by-products, such as buffalo milk, makes it a species of significant importance. Our focus is on protecting its genetic resources by preserving its sperm, as their numbers will decrease in the coming years and they are at risk of extinction. This study's goal was to ascertain how apigenin (A) and trans-ferulic acid (t-FA) affected the semen quality of Azari water buffalo bulls under cryopreservation. Pooled buffalo sperm (n = 35 ejaculations) were diluted in a Tris-based diluent also containing varying amounts of apigenin (0.2, 0.4, 0.6, and 0.8 mM) and trans-ferulic acid (2.5, 5, 10 and 20 mM). Following a freeze-thaw procedure, samples were assayed for total antioxidant capacity (TAC), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione activity (GSH), glutathione peroxidase (GPx), progressive motility and total motility, motility properties, plasma membrane functionality, and viability. Sixty days after insemination, the rectal examination was performed on 38 buffaloes that had undergone sexual breeding to confirm pregnancy. The results of the study show that the addition of A-0.2, A-0.4, and t-FA-10 to buffalo semen increases the percentage of intact plasma membrane, motility, and sperm viability, as well as the levels of GSH, GPx, CAT. and TAC. In addition, there is a decrease in MDA and DNA damage after cryopreservation. Furthermore, the results show that 0.4 mM apigenin significantly increases conception rates compared to the control group. The base extender of Tris supplemented with A (0.4 and 0.2 mM) and t-FA (10 mM) improves the antioxidant indices of both frozen and thawed buffalo sperm, which in turn improves post-thawing sperm quality and in vivo fertility improves buffalo sperm.

The Effects of Ferulic Acid, Tryptophan, and L-Glutamine on the Cryopreservation of Mouse Spermatozoa

In this study, the effects of ferulic acid (0.1, 1, ve 10 mM), tryptophan (5, 25, ve 50 mM), and L-glutamine (10, 50, ve 100 mM) at different doses added to 18% raffinose + 3% skimmed milk powder sperm extender on the freezing of mouse spermatozoa in liquid nitrogen were investigated. The combination of 18% raffinose + 3% skimmed milk powder without additives was used as the control group. Frozen spermatozoa were thawed in a 37°C water bath for 30 seconds. After freeze-thawing, motility, dead spermatozoa ratio, plasma membrane integrity, abnormal acrosome ratio, motility endurance (for 4 hours), and cell apoptosis tests were performed in Human Tubal Fluid (HTF). Compared with the control group after freezing and thawing, the highest motility and plasma membrane integrity were obtained in the 10 mM L-glutamine group with 56.6% ± 2.11% and 77.8% ± 0.87%, respectively (p < 0.05). In addition, when compared to the control group, the lowest rate of dead spermatozoa and abnormal acrosome was found in the 10 mM L-glutamine group as 26.0% ± 1.46% and 6.3% ± 1.09%, respectively (p < 0.05). The highest motility values for spermatozoa endurance were determined in the 10 and 50 mM L-glutamine groups up to the 4th hour compared to the control group (p < 0.05). In the evaluation of apoptosis in semen samples, there was no significant difference between the control, 0.1 mM ferulic acid, and 10 mM L-glutamine groups (p > 0.05). As a result, it was determined that the addition of 10 mM L-glutamine to the spermatozoa extender increased the motility, viable spermatozoa, functional membrane integrity, intact acrosome ratios, or motility endurance after freeze-thawing and could be used successfully in the freezing extender of mouse spermatozoa.

Effect of Melatonin and Caffeine Supplementation to Freezing Medium on Cryosurvival of Peruvian Paso Horse Sperm Using a Two-Step Accelerating Cooling Rate

This research examined the antioxidant and cryoprotective effects of melatonin (ME) and caffeine (CAF) supplementation in freezing medium on the cryosurvival of Peruvian Paso horse sperm using a two-step accelerating cooling rate. Twenty ejaculates from four adult and fertile stallions were recovered, initially diluted with INRA-96®, and finally frozen with INRA-Freeze® with either no supplementation (as control), 1 μM ME, or 2 mM CAF using a two-ramp freezing system content inside a cryogenic-box and liquid nitrogen vapors. The sperm kinematic parameters and integrity of the plasma and acrosomal membranes of fresh semen and cryopreserved samples were evaluated using the CASA system (SCA-Evolution® 2018) and PI/fluorescein isothiocyanate-conjugated peanut (Arachis hypogaea) agglutinin double fluorescent test, respectively. The oxidative stress of post-thaw sperm samples was also assessed using the CellRox Deep Red fluorescence test. The results showed that curvilinear velocity and average-path velocity were greater (p < 0.05) after freezing with CAF than the control group. In addition, there were significance differences (p < 0.01) between stallions (1-4) in post-thaw kinematic parameters regardless of ME or CAF addition. Both ME and CAF improved (p < 0.05) the proportion of sperm with intact plasma membranes and intact acrosomes. Nevertheless, neither CAF nor ME improved the oxidative stress after the cryopreservation process.

Effect of Ferulic Acid on Semen Quality of Goat Bucks during Liquid Storage at 17 °C

This study investigated the effect of different concentrations of ferulic acid (FA) on the quality of goat semen preserved at 17 °C. First, semen was collected from three black-headed goat bucks using an artificial vagina. Then, the mixed semen was diluted with basal dilutions containing different concentrations of FA (0, 25, 50, 100, and 200 μmol/L) and stored at 17 °C. Sperm total motility, plasma membrane integrity, acrosome integrity, reactive oxygen species (ROS) levels, malondialdehyde (MDA) content, and total antioxidant capacity (T-AOC) were measured during semen storage. The results showed that sperm total motility, plasma membrane integrity, and acrosome integrity were significantly improved in the 50 μmol/L FA group compared with the control group (0 μmol/L) on days 1-5, and the level of T-AOC significantly increased, while the contents of ROS and MDA significantly reduced. Meanwhile, the goats' conception rate showed that supplementing semen with 50 μmol/L FA preserved at 17 °C for 3 days had no significant effect on fertility. Taken together, our findings suggest that adding 50 μmol/L FA in dilution at 17 °C can improve goat bucks' semen quality.

Influence of trans-ferulic acid on the quality of ram semen upon cold preservation

BACKGROUND

Due to lower antioxidant capacity and higher amounts of polyunsaturated fatty acids, ram spermatozoa are very susceptible during cooling process.

OBJECTIVES

The objective was to examine the effect of the trans-ferulic acid (t-FA) on the ram semen during liquid preservation.

METHODS

Semen samples were collected from the Qezel rams, pooled, and extended with the Tris-based diluent. Pooled samples enriched with different amounts of the t-FA (0, 2.5, 5, 10, and 25 mM) and preserved at 4°C for 72 h. Spermatozoa's kinematics, membrane functionality, and viability were assessed by CASA system, hypoosmotic swelling test, and eosin-nigrosin staining, respectively. Moreover, biochemical parameters were measured at 0, 24, 48, and 72 h.

RESULTS

Results showed that 5 and 10 mM t-FA improved forward progressive motility (FPM) and curvilinear velocity compared to the other groups at 72 h (p < 0.05). Samples treated with 25 mM t-FA showed the lowest total motility, FPM, and viability at 24, 48, and 72 h of storage (p < 0.05). Higher total antioxidant activity levels were observed in the 10 mM t-FA-treated group compared to the negative control at 72 h (p < 0.05). Treatment with 25 mM t-FA increased malondialdehyde amounts and decreased superoxide dismutase activity compared to other groups at the final time assessment (p < 0.05). Nitrate-nitrite and lipid hydroperoxides values were not affected by treatment.

CONCLUSIONS

The current study indicates the positive and negative influences of different concentrations of t-FA on the ram semen upon cold storage.

Beneficial Effect of Proline Supplementation on Goat Spermatozoa Quality during Cryopreservation

Sperm cryopreservation contributes to the extensive utilization of artificial insemination (AI) in the daily livestock industry. However, due to the presence of few sperm with good biological function in post-thaw goat sperm, its use has been limited for AI purposes. Hence, its improvement has been the focus of many research studies. This study aimed to investigate the effects of proline supplementation of the freezing medium on goat sperm. The goat semen was cryopreserved with freezing medium supplementation of different concentrations of proline (0, 0.5, 1, 2 and 4 mM). The post-thaw sperm motility patterns, membrane integrity, acrosome integrity, lipid peroxidation (LPO) levels, malondialdehyde (MDA) levels, total antioxidant capacity (T-AOC), proline dehydrogenase (PRODH) activity, superoxide dis-mutase (SOD) activity, glutathione (GSH) levels and GSH/GSSG were evaluated. Likewise, the expression and immunofluorescent localization of PRODH in post-thaw goat sperm was also detected. It was observed that addition of 2 mM proline to the freezing medium significantly enhanced post-thaw goat sperm total motility, progressive motility, straight-linear velocity (VSL), curvilinear velocity (VCL), average path velocity (VAP), straightness (STR), linearity (LIN), membrane integrity and acrosome integrity. Interestingly, PRODH was expressed in post-thaw goat sperm, especially in the post-acrosome and sperm tail. Addition of 2 mM proline also significantly increased the post-thaw sperm PRODH activity compared to the control. Moreover, post-thaw goat sperm LPO levels and MDA levels were reduced by supplementation of 2 mM proline. Furthermore, compared to the control, the values of post-thaw goat sperm T-AOC, SOD activity, GSH level and GSH/GSSG were also significantly increased in 2 mM proline treatment. Reduction of post-thaw goat sperm apoptosis in 2 mM proline treatment was also observed as the levels of Caspase3 and Caspase9 were decreased by the supplementation with 2 mM proline. These observations suggest that the addition of 2 mM proline to the freezing medium increased post-thaw goat sperm quality by reducing oxidative stress during cryopreservation. These findings also provide novel insights into the use of proline as an efficient additive to enhance post-thaw goat sperm quality during cryopreservation.

L-proline as a novel additive to cryopreservation media improved post-thaw quality of human spermatozoon via reducing oxidative stress

Sperm cryopreservation as a routine technique in assisted reproductive technique (ART) laboratories has detrimental effects on spermatozoa. Various methods have been introduced to improve it. The aim of this research was to evaluate the effects of L-proline supplementation in cryopreservation medium on normozoospermic semen samples. A total of 30 semen samples were collected from normozoospermic men. Cryopreservation media were supplemented with different concentrations of L-proline (0, 1, 2 and 4 mmol/L). The semen samples were cryopreserved. After thawing, sperm parameters and chromatin integrity (aniline blue (AB), toluidine blue (TB), sperm chromatin dispersion test (SCD) and chromomycin A3 (CMA3)), reactive oxygen species (ROS), and total antioxidant capacity (TAC) and malondialdehyde (MDA) levels were evaluated. A total of 4 mmol/L L-proline significantly improved progressive motility and viability (p < 0.05). MDA and ROS levels significantly diminished in samples were cryopreserved by 4 mmol/L L-proline supplemented cryopreservation media (p < 0.001). Also, it significantly increased TAC level. Also, chromatin damages (AB, TB and CMA3) significantly improved in samples were cryopreserved by 4 mmol/L L-proline supplemented cryopreservation media (p < 0.05). The results support that the usage of L-proline supplemented cryopreservation media to improve sperm quality after cryopreservation.

Ameliorative role of trans-ferulic acid on induced oxidative toxicity of rooster semen by β-cyfluthrin during low temperature liquid storage

Current study was designed to evaluate the effects of β-cyfluthrin, as a toxicant substance, and trans-ferulic acid (trans-FA), as a protective agent, on different parameters of rooster semen upon liquid storage. For this purpose, semen samples of roosters (Ross 308, n = 10, 32-wk-old) were collected twice a week. Good quality samples (≥70% progressive motion) were diluted, pooled and then divided for the purposes of the study. In the first experiment, motility of spermatozoa was evaluated following exposure to different concentrations of β-cyfluthrin (1, 2.5, 5, 10, 20, 40, and 80 µM) at 0, 24, and 48 h of storage. In the second experiment, constant doses of β-cyfluthrin (10 µM) alone or in combination with trans-FA (10, 25 mM) were assessed on motility and viability of spermatozoa at 0, 24, and 48 h time points. Moreover, amounts of malondialdehyde (MDA), total antioxidant capacity (TAC), total nitrate-nitrite, total hydroperoxide (HPO), and activity of superoxide dismutase (SOD) were evaluated in the homogenate of spermatozoa-diluent at studied time points. Results of the first experiment showed that amounts of β-cyfluthrin greater than 5 µM, significantly reduced the motility of spermatozoa at 24 and 48 h of storage (P < 0.05). The second experiment demonstrated that, trans-FA especially at 10, 25 mM doses restored the motility and viability of spermatozoa compared to β-cyfluthrin treated group (P < 0.05). Amounts of MDA (10, 25 mM), hydroperoxide (10, 25, and 50 mM), and nitrate-nitrite (10, 25, and 50 mM) were lower and TAC (10 and 25 mM) were greater in trans-FA + β-cyfluthrin treated groups compared to β-cyfluthrin alone treated samples (P < 0.05). However, activity of SOD did not show significant changes by the treatment (P > 0.05). It seems that trans-FA could ameliorate toxic effect of β-cyfluthrin via reduction of peroxidative (as evident by measurement of MDA) and nitrosative (as evident by measurement of nitrate-nitrite) reactions over cold preservation of rooster semen.

Evaluation of Microscopic, Flow Cytometric, and Oxidative Parameters of the Frozen-Thawed Bull Sperm in a Freezing Extender Containing Myo-Inositol

Introduction: This research was conducted to assess the effect of myo-inositol (MYO) in the freezing extender on the semen quality and oxidative stress parameters of frozen-thawed bull sperm. Materials and Methods: Semen samples were obtained from four bulls (n = 24, six ejaculates per bull), twice a week, and diluted into four equal aliquots in freezing extenders containing different concentrations of MYO (0, 2, 3, and 4 mg/mL). After a freezing/thawing process, velocity parameters, plasma membrane integrity, apoptosis status, malondialdehyde level, and oxidative stress parameters were assessed. Results: Supplementation of freezing extender with 3 mg/mL MYO resulted in higher rapid motility (62.22% ± 2.63%), progressive motility (77.45% ± 2.65%), viability (78% ± 0.91%), plasma membrane integrity (86 ± 0.85), catalase (20.03 ± 0.39 U/mL) activity, and lower significance of lipid peroxidation (3.60 ± 0.15 nmol/dL) than those of the control group (p < 0.05). A significantly lower percentage of normal morphology and intact acrosomes were observed for frozen-thawed semen in the extender supplemented with 4 mg/mL MYO than those of the control group (p < 0.05). Freezing of the sperm in the extender containing 3 mg/mL of MYO leads to a higher percentage of live cells (38.3 ± 2.76). Beat-cross-frequency, amplitude of lateral head displacement, linearity, total antioxidant capacity, total peroxidase activity, early apoptotic status, and superoxide dismutase activities were not affected by MYO levels in the extenders (p > 0.05). Conclusion: The findings of this study suggest that the supplementation of the freezing extender with 3 mg/mL MYO resulted in a higher quality of frozen-thawed bull sperm.

Effects of vitamin D supplementation in extender on sperm kinematics and apoptosis following the freeze-thaw process in normozoospermic and asthenozoospermic Holstein bulls

Background

Asthenozoospermia is a usual male infertility factor, characterized by decreased semen quality. It has been revealed that antioxidants improve sperm function, enhance endogenous antioxidant activities, and protect spermatozoa against oxidative damage during cryopreservation. This aimed to evaluate the effects of vitamin D on sperm kinematics and apoptosis in the semen of bulls with normozoospermia and asthenozoospermia after the freeze-thaw process. For this purpose, 32 semen samples of four Holstein bulls (normozoospermic, progressive motility > 70 %) and 32 semen samples of four bull (asthenozoospermic progressive motility < 40 %) were collected and pooled separately (normozoospermic and asthenozoospermic). Samples were then diluted into four equal aliquots of extender containing different vitamin D concentrations (0, 5, 10, and 50 ng/mL) and aspirated into a 0.5 mL straw.

Results

The percentages of sperm progressive motility and viability were significantly higher (P < 0.05) in 50 ng/mL of vitamin D in normozoospermic group. Sperm kinematics parameters including curvilinear velocity (VCL), straight-line velocity (VSL), and average path velocity (VAP) were significantly higher in the high dose (50 ng/mL) vitamin D-treated group compared to the low dose vitamin D-treated group (5ng/mL) in normozoospermic bull semen samples. The supplementation of the semen extender with different concentrations of vitamin D could not increase the rate of acrosome integrity in normozoospermic bulls compared to the control group (P < 0.05). In the asthenozoospermic group, 10 ng/mL vitamin D-treated group could increase the rate of plasma membrane integrity compared to 5 ng/mL vitamin D-treated group (P < 0.05). The percentages of early-apoptosis (P = 0.049) and late-apoptosis (P = 0.005) were significantly higher in the asthenozoospermic than the normozoospermic group.

Conclusions

The present study revealed that a high dose (50 ng/mL) of vitamin D protected normozoospermic bulls’ sperms from the freezing procedure and lead to higher quality of frozen-thawed bull sperm.

Role of Antioxidants in Cooled Liquid Storage of Mammal Spermatozoa

Cooled preservation of semen is usually associated with artificial insemination and genetic improvement programs in livestock species. Several studies have reported an increase in reactive oxidative species and a decrease in antioxidant substances and sperm quality parameters during long-term semen storage at refrigerated temperatures. The supplementation of antioxidants in extenders before refrigeration could reduce this detrimental effect. Various antioxidants have been tested, both enzymatic, such as superoxide dismutase and catalase, and non-enzymatic, such as reduced glutathione, vitamins E and C and melatonin. However, the problem of oxidative stress in semen storage has not been fully resolved. The effects of antioxidants for semen-cooled storage have not been reviewed in depth. Therefore, the objective of the present study was to review the efficiency of the supplementation of antioxidants in the extender during cooled storage of semen in livestock species.

Overview on the Antioxidants, Egg Yolk Alternatives, and Mesenchymal Stem Cells and Derivatives Used in Canine Sperm Cryopreservation

Sperm cryopreservation is a widely used assisted reproductive technology for canine species. The long-term storage of dog sperm is effective for the breeding of dogs living far apart, scheduling the time of artificial insemination that suits the female, and preventing diseases of the reproductive tract. However, spermatozoa functions are impaired during the freeze-thaw processes, which may decrease reproductive performance. Numerous attempts have been made to restore such impairments, including the use of cryoprotectants to prevent the damage caused by ice crystal formation, and supplementation of antioxidants to reduce reactive oxygen species generation due to osmotic stress during the procedure. Egg yolk derivatives, antioxidants, and, more recently, mesenchymal stem cells (MSCs) and their derivatives have been proposed in this research field. This review article will summarize the current literature available on the topic.

Coenzyme Q-10 improves preservation of mitochondrial functionality and actin structure of cryopreserved stallion sperm

Coenzyme Q-10 (CoQ-10) is a cofactor for mitochondrial electron transport chain and may be an alternative to improve sperm quality of cryopreserved equine semen. This work aimed to improve stallion semen quality after freezing by adding CoQ-10 to the cryopreservation protocol. Seven saddle stallions were utilized. Each animal was submitted to five semen collections and freezing procedures. For cryopreservation, each ejaculate was divided in three treatments: 1) Botucrio® diluent (control); 2) 50 μmol CoQ-10 added to Botucrio® diluent; 3) 1 mmol CoQ-10 added to Botucrio® diluent. Semen batches were analyzed for sperm motility characteristics (CASA), plasma and acrosomal membranes integrity and mitochondrial membrane potential (by fluorescence probes propidium iodide, Hoechst 33342, FITC-PSA and JC-1, respectively), alterations in cytoskeletal actin (phalloidin-FITC) and mitochondrial function (diaminobenzidine; DAB). The 1 mmol CoQ-10 treatment presented higher (P<0.05) amount (66.8%) of sperm cells with fully stained midpiece (indicating high mitochondrial activity) and higher (P<0.05) amount (81.6%) of cells without actin reorganization to the post-acrosomal region compared to control group (60.8% and 76.0%, respectively). It was concluded that the addition of 1 mmol CoQ-10 to the freezing diluent was more effective in preserving mitochondria functionality and cytoskeleton of sperm cells submitted to cryopreservation process.

Photobiomodulation preconditioned human semen protects sperm cells against detrimental effects of cryopreservation

The biological consequences of semen samples preconditioning with photobiomodulation (PBM) were studied on human sperm cells post cryopreservation. Donated semen samples were collected from 22 married men with normal sperm parameters according to World Health Organization (WHO) criteria. Included samples were divided into control and PBM-preconditioning (one session, 810 nm, diode laser, and 0.6 J/cm2) groups before cryopreservation procedure. Progressive sperm motility (PSM), morphology, viability, sperm mitochondrial membrane potential(MMP), intracellular reactive oxygen species (ROS) and lipid peroxidation of sperm cells were assessed post thawing. PBM preconditioning of cryopreserved semen samples most prominently increased the PSM percentage 30 min post thawing (p = 0.000).Application of PBM before cryopreservation significantly increased the number of viable spermatozoa (p = 0.000), increased significantly the number of spermatozoa with high MMP (p = 0.004) and decreased significantly the number of spermatozoa with low MMP post-thawing(P = 0. 007)compared to control group. Cryopreserved human sperm cells with PBM preconditioning showed significant decrease in the levels of intracellular ROS (47.66 ± 2.14 versus 60.42 ± 3.16, p = 0.002) and lipid peroxidation (3.06 ± 0.13 versus 3.68 ± 0.27, p = 0.05)compared to control group. Our findings, as the first evidence, indicated that PBM-preconditioning of human semen before cryopreservation provides a real and substantial advantage. This might lead to a novel strategy in improving PBM application in the procedures of assisted reproductive technologies.

Melatonin improves the motility and DNA integrity of frozen-thawed ram spermatozoa likely via suppression of mitochondrial superoxide production

The ability of the neurohormone melatonin to ameliorate cryopreservation-induced damage to spermatozoa has been demonstrated in several domestic species. However, it is unclear how these protective effects are conferred, with improvements in sperm quality ambiguously attributed to the general antioxidant activity of melatonin. To further investigate this phenomenon, ram spermatozoa were diluted in cryomedia with and without melatonin (0 [control], 0.1, 1, 10, and 100 μM) and assessed for motility, viability, DNA integrity, mitochondrial superoxide production, lipid peroxidation, and intracellular reactive oxygen species before freezing and after thawing (0, 3, and 6 h post-thaw). Before freezing, supplementation with melatonin at any concentration had no effect on any measure of sperm quality. However, post-thaw, spermatozoa frozen in the presence of any level of melatonin reduced mitochondrial superoxide production of spermatozoa (P < 0.001), decreased the level of sperm DNA fragmentation (P < 0.001), and increased the percentage of motile spermatozoa (P = 0.035). Melatonin supplementation did not influence the relative levels of lipid peroxidation in the sperm membrane, the levels of intracellular reactive oxygen species, or sperm membrane lipid disorder (P > 0.05). There was no difference in the percentage of viable spermatozoa between treatment groups pre- or post-freeze (P > 0.05). These results suggest that, in the ram, melatonin does not protect the quality of cryopreserved spermatozoa through a nondiscerning scavenging of reactive oxygen species as previously suggested. Rather, melatonin appears to specifically reduce mitochondrial superoxide production, altering sperm functionality, as opposed to merely increasing the percentage of live sperm.

Nicotinic Acid (Niacin) Supplementation in Cooling and Freezing Extenders Enhances Stallion Semen Characteristics

In the present study, we aimed to evaluate the possible protective effects of the nicotinic acid (NA) at three concentrations (10, 20, and 40 mM) on the equine cooled and frozen-thawed spermatozoa quality markers including viability, plasma membrane or acrosome integrity, DNA fragmentation, lipid peroxidation, and total oxidant levels. We also evaluated the effects of NA on preservation of the post-thaw sperm quality after 6 hours of cold storage before freezing. Five stallions were used for semen collections. The current experiment was repeated six times using pooled semen samples from two stallions, each time. We showed that NA at 20 and 40 mM concentrations could significantly improve the stallion sperm quality markers during cold storage. However, the protective effects were not different between 20 mM and 40 mM concentrations in most measures. Nicotinic acid could also improve the post-thaw stallion sperm quality at 10, 20, and 40 mM concentrations. However, the 40 mM concentration showed a negative impact on some post-thaw kinematic sperm parameters. Nicotinic acid at 10 and 20 mM concentrations could preserve the sperm cryo-tolerance to be frozen up to 8 hours after collection without a significant decline in most of the post-thaw sperm quality measures. Nicotinic acid could also decrease the level of the lipid peroxidation and total reactive oxygen/nitrogen species in the cooled and frozen-thawed spermatozoa, in a dose-dependent manner. Therefore, NA at 20 mM concentration could preserve most of the stallion sperm quality measures during cold storage (42 hours, 5°C) and enabled storage of cooled stallion semen for 6 hours before freezing without significant deterioration of the post-thaw sperm quality.

Melatonin protects sperm cells of Capoeta trutta from toxicity of titanium dioxide nanoparticles

In this study, it was aimed to determine the protective effects of melatonin (0.01, 0.1, and 1 mM) against 10 mg/L titanium dioxide nanoparticles (TiO2-NPs) on kinematic and oxidative indices in the sperm cells of Capoeta trutta. Therefore, TiO2 nanoparticles were synthesized primarily within the scope of the study. The synthesized nanoparticles were characterized by structurally different techniques. Then, melatonin and TiO2 were applied to Capoeta trutta sperm cells by in vitro. According to our data, all doses of melatonin showed protective effects on all velocities of sperm cells such as the straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) against TiO2-NPs, while 0.1 and 1 mM doses of melatonin improved the VSL value. Although TiO2-NPs increased total glutathione (tGSH), malondialdehyde (MDA) lipid peroxidation, and superoxide dismutase (SOD) compared to the control group, there were positive treatment effects for all doses of melatonin on antioxidant capacity of sperm cells. At the end of this research, it is suggested that over 0.1 mM dose of melatonin improves the velocity of sperm cells and it plays a protective role against the toxic effects of TiO2-NPs.

Determination of the activity and relative abundance of mRNA for antioxidant enzymes in stallion testicular and epididymal tissues: A comparison between two breeding seasons

The key prerequisite for successful insemination is sperm characterized to have positive values for morphological and biological variables which are determined by, among others, effective antioxidant protection during the lifespan of sperm cells. This study evaluated the activity and relative abundance of mRNA for antioxidant enzymes in stallion testicular and epididymal tissues during breeding (n = 5) and non-breeding (n = 5) seasons. The activity of superoxide dismutase (SOD) was greater (P < 0.05) during the breeding season, in particular in the testes and the caput epididymis, and SOD1 was the predominant isoform of the enzyme. The expression of the SOD3 gene was markedly less in the analyzed tissues, which indicates that this enzyme contributes to the antioxidant protection of the stallion reproductive tract. The activity of catalase (CAT) was less (P < 0.05) in the testes during both seasons while its relative abundances only during the breeding season. The greatest CAT activity was noted in the cauda epididymis during the breeding season. The activity of glutathione peroxidases (GPx) was greater (P < 0.05) in the testes than in other tissues and 10-fold greater during the breeding season. Similarly, relative abundance of GPx5 mRNA was greater (P < 0.05) in the caput epididymis than in the remaining tissues during both seasons. This study demonstrated that season has an ambiguous influence on the antioxidant defense system in stallion reproductive tissues. Seasonal differences in the present study, however, indicate that the reproductive system of stallions adapts well to environmental seasonal changes.