Quercetin improves the postthaw characteristics of cryopreserved sex-sorted and nonsorted stallion sperm

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

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

Effect of Mitoquinone on sperm quality of cryopreserved stallion semen

This study aimed to investigate the effect of mitochondria-targeted antioxidants (Mitoquinone, MitoQ) on the quality of frozen-thawed stallion semen. Semen samples collected from three fertile stallions aged 10 - 13 years, were filtered, centrifuged in a skimmed milk-based extender, and diluted to a final concentration of 50 × 106 sperm/mL in freezing medium. Diluted semen was divided into five experimental groups supplemented with MitoQ at concentrations of 0 (control), 25, 50, 100, and 200 nM and then subjected to freezing after cooling and equilibration. After thawing, semen was evaluated for motility and kinetics at different time points. Sperm viability, plasma membrane, acrosome, DNA integrity, mitochondrial membrane potential, apoptosis, and intracellular reactive oxygen species (ROS) concentrations were evaluated. The results revealed that MitoQ at concentrations of 25, 50, and 100 nM improved (P< 0.01) the total sperm motility after 30 minutes of incubation. In addition, 25 nM MitoQ improved the sperm amplitude of lateral head displacement values (P< 0.01) after 30 minutes of incubation. Conversely, negative effects on sperm motility, kinetics, and viability were observed with the highest tested concentration of MitoQ (200 nM). The various concentrations of MitoQ did not affect the plasma membrane, acrosome, and DNA integrity, or the mitochondrial membrane potential and intracellular ROS concentrations. In conclusion, supplementation of MitoQ during cryopreservation, had a mild positive effect on sperm motility and kinetics especially at a concentration of 25 nM, while the highest concentration (200nM) has a detrimental effect on motility and viability parameters of frozen-thawed stallion sperm.

Quercetin in semen extender improves frozen-thawed spermatozoa quality and in-vivo fertility in crossbred Kamori goats

This study investigated the antioxidant effect of quercetin-treated semen on frozen-thawed spermatozoa quality and in-vivo fertility in crossbred Kamori goats. In total, 32 ejaculates from four fertile bucks were diluted in Tris-based egg yolk extender with varying levels of quercetin (0, 1, 5, 10, and 15 μM). Qualified semen samples were pooled and frozen in French straws. The results revealed that the addition of quercetin in the semen extender increased (p < 0.05) frozen-thawed sperm total motility (TM), progressive motility (PM), rapid velocity (RV), average path velocity (VAP), straight line velocity (VSL), curvilinear velocity (VCL), and amplitude of lateral head (ALH) displacement in contrast to the control group. Quercetin supplementation had no effect on beat cross frequency (BCF), straightness (STR), and linearity (LIN) (p > 0.05). Quercetin showed significantly higher (p < 0.05) plasma membrane and acrosome integrity and viability (p < 0.05) of spermatozoa in contrast to the control group. Quercetin in the semen extender significantly increased (p < 0.05) superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and total antioxidant capacity (TAC) levels while reduced (p < 0.05) the contents of total oxidant status (TOS) and malondialdehyde (MDA), which were in contrast to the control group. Ultrasound results revealed that 24 out of 30 (80%) goats were found pregnant when semen was treated with 5 μM quercetin while the control group showed 18 out of 30 (60%) animals were pregnant. Thus, the study concluded that 5 μM quercetin-treated semen was found to be efficient, showed increased antioxidant status, and reduced oxidant production, leading to improved spermatozoa quality and in-vivo fertility in goats.

Effects of dietary basil (Ocimum basilicum) supplementation on reproductive hormones, semen parameters, and testicular development in Zandi male lambs

This study investigated the potential impact of feeding whole plant basil on sperm quality and the concentration of certain reproductive hormones in male lambs. A total of 18 Zandi male lambs with an initial weight of 28.8 ± 2.03 kg were included in a completely randomized design with three treatments and six repetitions. The experimental treatments included: 1) control (basal diet without basil), 2) diet containing 12.5 % basil, and 3) diet containing 25 % basil. The results showed that feeding basil to male lambs significantly increased testosterone concentration and decreased blood cortisol levels (P < 0.05). Additionally, feeding high levels of basil significantly improved sperm concentration, motility, and viability in the experimental samples, while reducing the level of complete abnormalities and malondialdehyde concentration (P < 0.05). The findings suggest that dietary supplementation of 25 % whole plant basil could be a useful strategy to improve sperm quality and increase testosterone secretion while reducing cortisol levels in male lambs.

Effect of quercetin, L-ergothioneine and H89 on sperm motility and kinematic pattern, plasma membrane functionality and in vitro heterologous fertilizing capacity of cryopreserved equine semen

Semen cryopreservation causes extensive chemical and physical damage to sperm structure, which generates premature aging and reduces viability and fertility of spermatozoa. The addition of antioxidants to freezing extenders can reduce the oxidative damage caused by excessive generation of reactive oxygen species (ROS), and the premature aging could be reduced by adding an enzyme inhibitor that prevents an anticipated capacitation. The aim of this study was to evaluate the in vitro effect of quercetin (Q), L-ergothioneine (E) and H89 addition to cryopreserved equine spermatozoa. Six experimental groups were stablished: control, Q, E, H89, H89Q and H89E. The analyzed parameters were sperm motility and kinematic using computer assisted sperm analysis (CASA), plasma membrane functionality with the hypoosmotic swelling test (HOST) and fertilizing capability with in vitro heterologous fertilization. Quercetin reduced curvilinear velocity (VCL) and increased beat-cross frequency (BCF), while its combination with H89 (H89Q) reduced total motility, progressive motility, VCL and hyperactive sperm (HA). Likewise, H89 and its combination with E (H89E) decreased VCL and amplitude of lateral head displacement (ALH). No significant differences were observed among treatments for membrane functionality and fertilizing capacity of sperm. In conclusion H89 in combination with Q and E reduced sperm motility or some kinematic parameters. However, they did not influence plasma membrane functionality and in vitro fertilizing capacity of frozen-thawed equine semen.

Synergistic effect of extracellular adenosine triphosphate and quercetin on post-thaw quality and fertilization potential of Lohi ram sperm

This study determined the individual and combined effects of extracellular adenosine triphosphate (ATP) and quercetin (QUE) on the quality of post-thawed sperm and the fertilization potential of Lohi rams. In experiment 1, semen samples from four Lohi rams were pooled and extended with different concentrations of ATP or QUE (control; no ATP or QUE, 1 or 2 mM ATP and 10 or 20 μM QUE). In experiment 2, pooled semen samples were extended with various combinations of ATP and QUE (control; no ATP and QUE, 1 mM ATP + 10 μM QUE, 1 mM ATP + 20 μM QUE, 2 mM ATP + 10 μM QUE and 2 mM ATP + 20 μM QUE). All samples in both experiments were cryopreserved and analyzed for post-thawed sperm quality. In experiment 3, the best combination of ATP and QUE from experiment 2 was to extend semen, which was then used for laparoscopic insemination in estrus-synchronized ewes (n = 83). The results of experiment 1 showed that 1 mM ATP and 20 μM QUE treatments resulted in higher total motility, progressive motility, viability, plasma membrane intactness (PMI), and motion kinetics (VCL, VSL, VAP, LIN, and STR) compared to other treatments (p < 0.05). In experiment 2, the 1 mM ATP +10 μM QUE-treated group exhibited significantly higher total and progressive motility, PMI, and motion kinetics (VSL, VCL, VAP, STR, and BCF) compared to the control group (p < 0.05). In experiment 3, the fertilizing potential of sperms treated with 1 mM ATP +10 μM QUE was greater than that of untreated controls (58.1% vs. 27.5%, respectively, p-value = 0.012). In conclusion, the quality of post-thawed ram semen is enhanced when the extender is supplemented with extracellular 1 mM ATP and 20 μM QUE, whether used separately or in combination with 1 mM ATP and 10 μM QUE. Furthermore, the inclusion of 1 mM ATP and 10 μM QUE together in the extender significantly improves in vivo fertility in Lohi ram.

The Effects of Silymarin Supplementation on Post-Thawed Human Sperm Functional Parameters

This study investigated the effect of silymarin on human sperm quality during cryopreservation. Samples were collected from 20 normospermic individuals, and each sample was divided into different concentrations of silymarin comprising the following groups: (0, 20, 100, 500, and 1000 μg/mL silymarin). Sperm quality parameters, such as plasma membrane integrity, mitochondrial membrane potential, acrosomal membrane integrity, and caspase 3 were estimated. Silymarin concentrations of 100-500 μg/mL significantly increased motility, plasma membrane integrity, and mitochondrial activity compared with the frozen control group. Acrosomal integrity was increased in the 1000 μg/mL silymarin group. Moreover, 20 and 100 μg/mL concentrations significantly decreased the percentage of caspase 3. The addition of silymarin antioxidant to the frozen medium reduced damage in the sperm after freezing and thawing. This is the first study that showed silymarin can be useful in cryopreservation of human sperm.

Use of the flavonoid taxifolin for sperm cryopreservation from the threatened Bermeya goat breed

Taxifolin is a plant flavonoid effective as an antioxidant. This study aimed to assess the effect of adding taxifolin to the semen extender during the cooling period before freezing on the overall post-thawing sperm variables of Bermeya goats. In the first experiment, a dose-response experiment was performed with four experimental groups: Control, 10, 50, and 100 μg/ml of taxifolin using semen from 8 Bermeya males. In the second experiment, semen from 7 Bermeya bucks was collected and extended at 20 °C using a Tris-citric acid-glucose medium supplemented with different concentrations of taxifolin and glutathione (GSH): control, 5 μM taxifolin, 1 mM GSH, and both antioxidants. In both experiments, two straws per buck were thawed in a water bath (37 °C, 30 s), pooled, and incubated at 38 °C. Motility (CASA) was assessed at 0, 2, and 5 h, and sperm physiology was assessed at 0 and 5 h by flow cytometry (viability, intact acrosome membrane, mitochondria membrane potential, capacitation, intracellular reactive oxygen species -ROS-, mitochondrial superoxide, and chromatin status). In experiment 2, an artificial insemination trial (AI) was included with 29 goats for testing the taxifolin 5-μM treatment on fertility. Data were analyzed with the R statistical environment using linear mixed-effects models. In experiment 1 and compared to the control, T10 increased progressive motility (P < 0.001) but taxifolin decreased total and progressive motility at higher concentrations (P < 0.001), both post-thawing and after the incubation. Viability decreased post-thawing in the three concentrations (P < 0.001). Cytoplasmic ROS decreased at 0 and 5 h at T10 (P = 0.049), and all doses decreased mitochondrial superoxide post-thawing (P = 0.024). In experiment 2, 5 μM taxifolin or 1 mM GSH (alone or combined) increased total and progressive motility vs. the control (P < 0.01), and taxifolin increased kinematic parameters such as VCL, ALH, and DNC (P < 0.05). Viability was not affected by taxifolin in this experiment. Both antioxidants did not significantly affect other sperm physiology parameters. The incubation significantly affected all the parameters (P < 0.004), overall decreasing sperm quality. Fertility after artificial insemination with doses supplemented with 5 μM taxifolin was 76.9% (10/13), not significantly different from the control group (69.2%, 9/13). In conclusion, taxifolin showed a lack of toxicity in the low micromolar range and could benefit goat semen cryopreservation.

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

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

Quercetin: Putative effects on the function of cryopreserved sperms in domestic animals

Quercetin is one of the most used antioxidant flavonoids and largely exists in many fruits and vegetables because of its capability to scavenge the free reactive oxygen species (ROSs) by repressing lipid peroxy radical fusion, metal ion chelating through enzyme inhibition, and adopting the repair mechanisms. It also exhibits various biological actions, including antioxidative, anti-inflammatory and antimicrobial activities. Furthermore, it contributes well to sustaining the endogenous cellular antioxidant defence system. The process of cryopreservation is associated with increased oxidative stress, and some steps are potential sources of ROSs, including the method of semen collection, handling, cryopreservation culture media, and thawing, which result in impaired sperm function. Several antioxidants have been proposed to counteract the harmful impact of ROS during semen cryopreservation. The antioxidant capability of quercetin has been verified in different animal species for providing valuable defence to sperm during the cryopreservation process. The beneficial properties of quercetin on various parameters of fresh and post-thaw sperm in different species are clarified in this review. More in-depth investigations are required to clarify quercetin's mechanism of action in different animal species.

Impact of quercetin, carnosine, and ozone in the cryopreservation on Nellore (Bos indicus) semen

The objective of this study was to reduce the effects of cryoinjury caused in bovine semen by cryopreservation. Ejaculates were collected from Nellore bulls and subjected to freezing in C (control), ozone (15, 30, and 60 µg mL^-1 of ozone), quercetin (25, 50, and 100 µg mL^-1 of quercetin), and carnosine groups (100, 200, and 300 ng mL^-1 of carnosine). Samples were evaluated post-thaw (M0) and post-rapid thermoresistance test (M30) for sperm kinetics (total motility, progressive motility, curvilinear speed, linearity and amplitude of lateral head displacement) and cell structure viability (plasma membrane integrity, acrosomal integrity, mitochondrial potential, membrane fluidity, and lipid peroxidation). There were no differences (P > 0.05) between the control, quercetin, and carnosine-treated groups for the parameters evaluated at M0 and M30. In turn, supplementation with ozone resulted in lower values for sperm kinetics (P < 0.05) and lower mitochondrial potential at M30 (P < 0.05). Quercetin and carnosine at the concentrations used did not promote significant gains in frozen semen, nor did they demonstrate cytotoxicity. We expected to obtain positive results with the use of ozone. Nonetheless, the addition was harmful to the parameters of sperm kinetics, and its effect was not observed as a possible pro-antioxidant. We believe that the fact that the gas did not harm the sperm structure opens avenues for tests with lower dosages, since, by reducing its concentration, we could minimize the damage to sperm kinetics.

Evaluation of the effects of hesperidin on fresh and frozen-thawed semen quality using two different cryopreservation methods in Simmental bull

In the industry of bull semen freezing centers, one-step and two-step semen dilution protocols are two standard and well-known methods in semen freezing process. As the freezing/thawing processes cause detrimental effects on sperm function, the addition of antioxidants can improve sperm characteristics. Hesperidin (Hesp) is an antioxidant used as the male reproductive protective agent. Therefore, the aim of this study was to investigate two different dilution methods, as well as to evaluate Hesp supplementation influence on sperm characteristics in fresh and frozen thawed semen. Semen samples were collected from 12 Simmental bulls. Two separate examinations were conducted in, with and without Hesp supplementation groups. Statistical analysis was performed by an independent t-test, Mann Whitny test, MANOVA and ANOVA tests. In comparison to the one and two-step dilution protocols without Hesp supplementation, the two-step dilution showed greater cryoprotective potential. In the Hesp supplemented group, each semen sample was divided into six equal parts for experimental groups (dilution step method/µM of Hesp). In the both one and two step dilution protocols, significant improvements were detected in semen motility parameters by Hesp administration. Also, oxidative stress status was reduced in seminal plasma of Hesp treatment groups. Interestingly, in comparison with Hesp dosage, 1µM was shown to have greater semen cryoprotective potential. In conclusion,

Spirulina supplementation to the semen extender influences the quality and antioxidant parameters of chilled or cryopreserved Arabian stallion spermatozoa

The present study attempted to investigate the effect of various concentrations of spirulina platensis additions to the semen extender on Arabian stallion spermatozoa quality. Semen samples were collected with artificial vagina from five fertile stallions and diluted with an extender containing spirulina (2, 4, 6, and 8 mg/100 mL) or without spirulina (control). Aliquots of diluted semen were cooled (5°C, 90 min.) and frozen (-196°C, 7 d), then physical traits of thawed spermatozoa were examined. Furthermore, antioxidant activities of superoxide dismutase (SOD), glutathione reductase (GSR), total antioxidant capacity (TAC), and malondialdehyde (MDA) were measured in post-cooling and freezing spermatozoa. The results indicated that spirulina supplemented with the extender had no effect (P > 0.05) on sperm quality parameters and antioxidant activities after cooling. However, adding 6 mg spirulina/100 mL to the freezing extender improved (P < 0.05) the speed parameters and total motility percentage of frozen/thawed spermatozoa. Besides, supplementation of freezing extender with the previous level increased (P < 0.05) TAC, SOD and GSR concentrations/activities (0.86 ± 0.32 mM/L, 323.70 ± 12.81 U/mL, and 38.65 ± 1.90 U/mL, respectively) compared with the control (0.70 ± 0.25 mM/L, 165.80 ± 8.12 U/mL, and 25.70 ± 1.83 U/mL, respectively). While, lipid peroxidation of the frozen-thawed semen was reduced (P < 0.05, 17.97 ± 1.30 µmol/ L) compared with the control (29.39 ± 1.89 µmol/ L). Accordingly, the present results revealed that additions of 6 mg spirulina/100 mL to the freezing extender improved semen quality and reduced cryodamage of the Arabian stallion spermatozoa.

Quercetin improves the apoptotic index and oxidative stress in post-thaw dog sperm

Freeze storage of ejaculated sperms is a crucial technique for the semen preservation of valuable pet animals such as dogs. The current study was conducted to investigate if quercetin (QRN) may ameliorate apoptosis and oxidative stress in post-thaw dog sperm. Herein, we evaluated the post-thaw apoptosis and oxidative stress after treatment with QRN (control, 25, 50, and 100 μM) in the freezing of dog semen. Reactive oxygen species levels were significantly affected (p < 0.05) between the various concentrations of QRN and the control (17.56 ± 1.02, 7.54 ± 0.48, 5.66 ± 0.80, and 10.41 ± 0.69), respectively. The apoptosis index was 9.1 ± 1.34, 6.66 ± 0.58, 6.77 ± 0.66, and 5.38 ± 0.86 in the control, and 25, 50, and 100 μM QRN treatment groups, respectively (p < 0.05). The effects of ameliorated cryo-induced damage by QRN on post-thaw sperm quality were also observed through improved structural and functional tests. Sperm treated with 50 μM QRN showed significantly higher motility (51.8 ± 2.1% vs. 43.1 ± 1.4%, P < 0.05), survival rates (46.9 ± 0.7% vs. 43.9 ± 0.4%, P < 0.05), and mucus penetration than control group, respectively. Results also indicated that higher concentrations of QRN (100 μM) were not effective on sperm quality and parameters when compared with the medium levels (50 μM). In conclusion, supplementation of freezing buffer with 50 μM QRN reduced oxidative damage and improved the quality of post-thaw dog sperm.

Chlorogenic Acid Improves Quality of Chilled Ram Sperm by Mitigating Oxidative Stress

Simple Summary

Sheep sperm is extremely sensitive to reactive oxygen species (ROS) and can produce a large amount of ROS during chilling storage, leading to a decline in semen quality. Adding antioxidants is an important method to improve semen quality. Chlorogenic acid (CGA) is a kind of plant extract with an antioxidant capacity, which can effectively eliminate free radicals and improve the antioxidant capacity of semen. However, its role in the chilling storage of Hu ram semen is not clear. Therefore, CGA with different concentrations was added to chilling storage extender to investigate its effect on chilled ram sperm. The results of this study revealed that CGA with proper concentration had a positive effect on chilled Hu ram sperm and 0.8 mg/mL CGA had the best effect.

Abstract

The purpose of this study was to investigate whether the addition of chlorogenic acid (CGA) to a sheep semen extender could improve the quality of chilled sheep sperm. Ejaculates (n = 80) were collected from five Hu rams with an artificial vagina. The ejaculates were mixed and divided into five equal parts, diluted with a CGA-free Tris–egg yolk extender (control), or supplemented with 0.2, 0.4, 0.8, and 1.2 mg/mL. The sperm kinematic parameters (viability, progressive motility), functional integrity of plasma membrane and acrosome, adenosine triphosphate (ATP) concentration and antioxidant parameters (Catalase (CAT), Superoxide dismutase (SOD) activity, total antioxidant capacity (T-AOC), ROS level and Malondialdehyde (MDA) content) were evaluated during storage of the semen. The results indicated that: PM, plasmatic membrane integrity and acrosomal integrity in 0.8 mg/mL CGA were higher (p < 0.05) from day 1 to 5. The ROS level in CGA groups was lower than the control (p < 0.05). CAT, SOD, ATP, and T-AOC were highest at 0.8 mg/mL concentration within 1 to 5 days. The above results indicated that the right concentration of CGA improved the quality of Hu ram sperm during chilling storage.

L-carnitine added to post-thawed semen acts as an antioxidant and a stimulator of equine sperm metabolism

The objective of this study was to enhance the in vitro sperm quality and in vivo fertility of frozen-thawed equine semen by the addition of l-carnitine (LC) to post-thawed semen. Different concentrations of LC were added to thawed samples to obtain four treatments control and 0.5, 1 and 2 mM LC. In the in vitro experiments, sperm motility and kinematics, membrane integrity and intracellular calcium ion concentration ([Ca²⁺ ]_i ) were investigated, and the antioxidant bioactivity of LC was assessed by measuring hydrogen peroxide and nitrite concentrations (NO₂ ^- ). The fertility rate was assessed via the artificial insemination of mares. The treatment with 1 mM LC increased sperm [Ca²⁺ ]_i (60.6 ± 0.05 AU), reduced nitrite concentration (39.1 ± 14.9 µM/µg protein), increased the sperm straightness percentage (STR: 78.3 ± 5.3%) and increased the pregnancy rate (75%) as compared to the control ([Ca²⁺ ]_i 48.4 ± 0.05 AU, NO₂ ^- concentration 63.1 ± 14.4 µM/µg protein, STR 67.5 ± 7.9%, 12.5% pregnancy rate, p < 0.05). These results suggest that 1 mM LC acts as an antioxidant and stimulator of sperm metabolism in post-thawed equine semen, increasing the fertility rate. Thus, addition of LC might be an alternative to improve the fertility of poor quality post-thawed equine semen.

Supplementation of Avian Semen Extenders with Antioxidants to Improve Semen Quality-Is It an Effective Strategy?

Oxidative stress in sperm is a phenomenon related to the increasing rate of oxidation of cellular components and the excessive production of reactive oxygen species (ROS). The high content of polyunsaturated fatty acids in bird sperm cell membranes renders these cells particularly susceptible to lipid peroxidation (LPO). Therefore, to ensure the proper functioning of cells, it is necessary to have a balance between the formation of ROS and the protective action of the antioxidant system. This review aims firstly to briefly introduce the antioxidant system characteristics of avian semen. Secondly, we summarize the recent knowledge regarding progress in extender supplementation using antioxidants and other compounds to improve avian semen quality parameters and fertility rates. The review focuses on enzymes, vitamins, amino acids, proteins, some plant extracts, and other compounds that can be used to supplement the extenders to reduce the formation of oxidants in poultry semen and maintain its quality and enhance its fertility.

Quercetin effect on the efficiency of ovine oocyte vitrification at GV stage

The widely adopted method of vitrification is known to induce some negative effects on oocytes. In order to enhance the efficiency of this process performed on ovine oocytes at germinal vesicle stage, vitrification and warming (VW) solutions, and maturation media were supplemented with 5 μM Quercetin (Q). Four groups of vitrified and fresh immature oocytes were subjected to IVM, IVF and IVC, and their survival rate, apoptosis, nuclear status and developmental competence were assessed. Non-vitrified oocytes treated with Quercetin experienced higher cleavage rate relative to those matured without Quercetin (p < 0.05). Supplementation of VW and maturation media with Quercetin resulted in increased survival, cleavage and total blastocyst rates relative to the untreated oocytes. The post-IVM survival rate of non-vitrified oocytes showed no difference among those matured with and without Quercetin, but was higher for oocytes vitrified, warmed and matured with Quercetin relative to VW group lacking Quercetin. The proportion of early-apoptotic (AV+) oocytes was affected by Quercetin supplementation in both control and VW groups (p < 0.05). The number of AV positive oocytes was lower and the proportion of oocytes reaching MII stage was greater in non-vitrified and VW groups matured with Quercetin, in comparison with their untreated respective controls (p < 0.05). There was no difference in the number of late-stage apoptotic oocytes among different groups. It is concluded that supplementing vitrification and warming solutions with Quercetin endows vitrified ovine oocytes with protective potential against early apoptotic damage, and improves viability, maturation rate and developmental competence at GV stage.

The Role of Selected Natural Biomolecules in Sperm Production and Functionality

Emerging evidence from in vivo as well as in vitro studies indicates that natural biomolecules may play important roles in the prevention or management of a wide array of chronic diseases. Furthermore, the use of natural compounds in the treatment of male sub- or infertility has been proposed as a potential alternative to conventional therapeutic options. As such, we aimed to evaluate the effects of selected natural biomolecules on the sperm production, structural integrity, and functional activity. At the same time, we reviewed their possible beneficial or adverse effects on male reproductive health. Using relevant keywords, a literature search was performed to collect currently available information regarding molecular mechanisms by which selected natural biomolecules exhibit their biological effects in the context of male reproductive dysfunction. Evidence gathered from clinical trials, in vitro experiments and in vivo studies suggest that the selected natural compounds affect key targets related to sperm mitochondrial metabolism and motion behavior, oxidative stress, inflammation, DNA integrity and cell death. The majority of reports emphasize on ameliorative, stimulating and protective effects of natural biomolecules on the sperm function. Nevertheless, possible adverse and toxic behavior of natural compounds has been indicated as well, pointing out to a possible dose-dependent impact of natural biomolecules on the sperm survival and functionality. As such, further research leading to a deeper understanding of the beneficial or adverse roles of natural compounds is necessary before these can be employed for the management of male reproductive dysfunction.

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.

Quercetin and Naringenin Provide Functional and Antioxidant Protection to Stored Boar Semen

In this study, we evaluated the impact of 5-50 μM quercetin (QUE) and naringenin (NAR) on extended boar spermatozoa in the BTS (Beltsville Thawing Solution) medium for 72 h. Spermatozoa motion, membrane, acrosome, and DNA integrity were investigated immediately after sample dilution (0 h) as well as after 24 h, 48 h, and 72 h of semen storage. Furthermore, reactive oxygen species (ROS) and superoxide production, as well as the extent of oxidative damage to the sperm proteins and lipids, were assessed to determine the potential of QUE and NAR to prevent a potential loss of sperm vitality due to oxidative stress development. Our results indicate that the most notable parameter influenced by QUE was the mitochondrial activity, which remained significantly higher throughout the experiment (p < 0.001 and p < 0.0001; 10 μM), and which correlated with the most prominent maintenance of sperm motility (p < 0.01, 48 h; p < 0.05, 72 h). A significant membrane stabilization (p < 0.01, 24 h and 48 h; p < 0.0001, 72 h) and prevention of lipid peroxidation (p < 0.05, 24 h and 48 h; p < 0.01, 72 h) was primarily observed following administration of 10 and 25 μM NAR; respectively. Administration of 10 μM QUE led to a significant decrease of superoxide (p < 0.0001, 48 h and 72 h) while the most notable decline of ROS generation was recorded in the case of 10 and 25 μM NAR (p < 0.001). This study may provide new information on the specific mechanisms of action involved in the favorable effects of natural biomolecules on spermatozoa.

Update on advanced semen-processing technologies and their application for in vitro embryo production in horses

The increased commercialisation of intracytoplasmic sperm injection (ICSI) in horses creates more opportunities to incorporate advanced reproductive technologies, such as sex-sorted, refrozen and lyophilised spermatozoa, into a breeding program. This paper reviews the status of these semen-handling technologies in light of their use in equine ICSI programs. Pregnancies have been achieved from each of these advanced technologies when combined with ICSI in horses, but refinements in the semen-handling processes underpinning these technologies are currently being explored to produce more reliable and practical improvements in the results from equine ICSI.

The Relationship of Mitochondrial Membrane Potential, Reactive Oxygen Species, Adenosine Triphosphate Content, Sperm Plasma Membrane Integrity, and Kinematic Properties in Warmblood Stallions

Equine sperm possesses a unique physiology because its energy supply is mostly dependent on oxidative phosphorylation of mitochondria as an aerobic source of adenosine triphosphate (ATP) generation. The present study was, therefore, conducted to investigate the relationship between sperm kinematic and functional variables in stallions. Semen samples were collected from five warmblood stallions (three ejaculates from each stallion), diluted with INRA96 and transferred to the laboratory. Next, sperm motility, mitochondrial membrane potential (MMP), production of superoxide anion (as a reactive oxygen species; ROS), ATP content, and plasma membrane integrity were assessed. Motion and functional characteristics differed among investigated stallions (P < .05). In addition, it was revealed MMP was positively correlated with the level of ROS and ATP content and progressive motility (P < .05). The level of ROS was positively correlated with ATP content and negatively correlated with plasma membrane integrity and straightness (P < .05). Adenosine triphosphate content was positively correlated with progressive motility, curvilinear velocity, average path velocity, and beat cross frequency and reversely correlated with plasma membrane integrity and straightness (P < .05). Plasma membrane integrity was positively correlated with straight line velocity, linearity, and straightness and negatively correlated with curvilinear velocity (P < .01). In conclusion, the present study substantiated that kinematic and functional characteristics varied among various warmblood stallions. Furthermore, the present study implicated although higher mitochondrial activity increases ATP synthesis, it leads to elevated superoxide anion production, which could culminate in disintegration of the sperm plasma membrane, thereby altering motion characteristics and swimming pattern of sperm.

Effect of quercetin on the motility of cryopreserved canine spermatozoa

The addition of an antioxidant to cryopreservation solutions for preventing oxidative stress to sperm from several species, including that from humans, has been studied previously. Quercetin is a flavonoid contained in subarctic trees with freeze resistance and is known to be a strong antioxidant. Therefore, the effect of quercetin on the cryopreservation of dog spermatozoa was examined in this study. The proportions of total motile spermatozoa were significantly higher at 30, 60, 90, 120, and 150 min and at 60, 120, and 150 min after thawing in groups treated with 5 μg/ml and 10 μg/ml of quercetin dissolved in 0.1% DMSO added to the second extender based on skim milk compared to that in the control group, respectively. There were no differences between the experimental groups in the proportion of total motile spermatozoa during the observation periods. The proportion of total motile spermatozoa among those treated with 5 μg/ml of quercetin in 0.1% DMSO was improved by approximately 10-20% at 30-180 min after thawing compared to that in the control group. To evaluate the fertility of cryopreserved spermatozoa treated with quercetin, 2 × 10⁸ spermatozoa were transcervically inseminated into bitches, and a total of 18 puppies were delivered in three bitches. These results indicated that supplementation of quercetin as a cryoprotectant to the skim milk-based extender improved the motility of cryopreserved spermatozoa from dogs compared to those of the control group. And fertility of cryopreserved spermatozoa with quercetin supplementation was proven with higher efficiency.

Protective effect of vitamin C and lycopene on the in vitro fertilization capacity of sex-sorted bull sperm by inhibiting the oxidative stress

The fertilization capacity of sex-sorted sperms is seriously decreased, which inhibits its wide application. However, little information is still available about the effect of vitamin C (VC) and lycopene (Lyc) on the fertilization capacity of sex-sorted bull sperm. In this study, the washing medium and fertilization medium of sex-sorted sperm from three bull individuals were supplemented with different concentrations of VC (0, 1 × 10^-3 , 1 × 10^-4 , 1 × 10^-5 , 1 × 10^-6  M) or Lyc (0, 1 × 10^-4 , 1 × 10^-5 , 1 × 10^-6 , 1 × 10^-7 ). After washing twice and incubation for 1.5 hr, the malondialdehyde (MDA) level, phosphatidylserine (PS) translocation, membrane potential (Δψm) and IVF (in vitro fertilization) ability of sex-sorted sperm were investigated. For the sex-sorted sperm of bulls A, B and C, 1 × 10^-3  M VC or 1 × 10^-4  M Lyc treatment significantly decreased their MDA levels and PS translocation and increased their Δψm levels and cleavage rates after IVF. When blastocysts were concerned, 1 × 10^-4  M Lyc significantly improved the blastocyst rates and their IFN-tau expression of bulls A and C. In conclusion, supplementation of 1 × 10^-3  M VC or 1 × 10^-4  M Lyc in washing and fertilization medium contributed greatly to improving the fertilization capacity of sex-sorted bull sperm during IVF procedure.

Quercetin supplemented casein-based extender improves the post-thaw quality of rooster semen

The advantageous influence of quercetin (Q) supplementation in an extender has not yet been evaluated for rooster semen cryopreservation. This research was purposely conducted in order to assess the effect of different quercetin concentrations added into an extender on the sperm quality of the rooster subsequent to a freezing-thawing process. After the freezing-thawing process, spermatozoa quality parameters (membrane functionality, acrosome integrity, motility, viability, and abnormal morphology), endogenous enzymes (SOD, CAT, and GPx), mitochondrial activity, DNA fragmentation index, lipid peroxidation (MDA), and ROS were all evaluated. A total of 75 neat pooled ejaculates (3 ejaculates/rooster) were collected from 25 arbor acres roosters (24 wks) twice a week using abdominal massage technique, then divided into five equal aliquots and diluted with an extender containing different doses of Q (CS-Q) as follows: casein extender without Q (control only), casein extender containing 0.040 mg/mL quercetin (CS-Q 0.040), 0.020 mg/mL quercetin (CS-Q 0.020), 0.010 mg/mL quercetin (CS-Q 0.010), and 0.005 mg/mL quercetin (CS-Q 0.005). Our results depicted that adding to the extender with a 0.010 mg/mL Q enhanced (P < 0.01) sperm motility, membrane function, viability, mitochondrial activity, intact acrosome (P < 0.05), SOD (P < 0.001), CAT, and GPx (P < 0.01) compared to the control group at post-thaw. Compared to the control group and other treatment groups after the freeze-thawing process, the addition of 0.005 mg/mL Q into the extender also showed higher (P < 0.05) improvement in the quality of sperm parameters and a higher (P < 0.01) SOD and CAT but did not improve mitochondrial activity and sperm viability. In addition, there was a lower degree of DNA fragmentation index, lower (P < 0.05) lipid peroxidation and ROS in frozen-thawed sperm treated with 0.010 mg/mL and 0.005 mg/mL Q than in control and the other treatment groups. In addition, 0.020 mg/mL Q supplementation into the extender also reduced DNA fragmentation and improved GPx activity compared to the control group at post-thaw. Different concentrations of Q 0.010 and 0.005 mg/mL added to the extender reduced the percentage of abnormal spermatozoa compared to the other groups. The results of this study showed for the first time that the inclusion of an extender with a suitable quercetin concentration of 0.010 mg/mL improved the post-thawed quality of rooster semen.

Effect of quercetin loaded liposomes or nanostructured lipid carrier (NLC) on post-thawed sperm quality and fertility of rooster sperm

The aim of this study was to investigate the effects of 10, 15 and 20 μM quercetin, alone or loaded in nanoliposomes or in nanostructured lipid carrier (NLC) on sperm rooster cryopreservation and fertility performance. Sperm motility, viability, abnormalities, membrane integrity, mitochondrial activity, apoptosis status, lipid peroxidation (LP), GPX, SOD, TAC and fertility and hatchability rate were investigated after freeze-thawing. A significantly higher percentage (P < 0.05) of sperm total motility was obtained in sperm cryopreserved with 15 μM quercetin loaded NLC compared to diluent with 10 and 20 μM quercetin and to 10, 15 and 20 μM quercetin loaded nanoliposomes, 20 μM quercetin loaded NLC and control group. Also, 15 μM quercetin loaded NLC was significantly higher in progressive motility, VSL, VAP and VCL parameters compared to control group. The percentage of viability, membrane integrity, mitochondria activity, TAC, and GPx increased in semen exposed to 15 μM quercetin loaded NLC group. Likewise, the lowest level (P < 0.05) of malondialdehyde (MDA) was acquired in samples treated with 15 μM quercetin and quercetin loaded NLC group in comparison to the control group. Abnormal form, SOD, and early apoptosis were not (P > 0.05) affected by different levels of quercetin. Fertility and hatchability rate showed higher levels in 15 μM quercetin and quercetin loaded NLC group compared with control group. In conclusion, it seems that quercetin loaded NLC enhanced the antioxidant effect of quercetin by improving post-thawed sperm quality and fertility of rooster sperm.

Effect of relaxin on semen quality variables of cryopreserved stallion semen

The aim of the study was to ascertain effects of different concentrations of relaxin added to extender medium during the pre-freezing incubation periods on quality variables of stallion frozen-thawed spermatozoa. Semen samples collected from three stallions were filtered, diluted with skim milk, and centrifuged at 600g for 10 min. Sperm pellets were suspended in BotuCrio freezing medium to a final concentration of 50 × 10⁶ sperm/mL. The diluted semen was divided into five experimental groups supplemented with 0 (control), 12.5, 25, 50, or 100 ng/mL of relaxin. The semen samples were transferred into 0.5 mL straws, equilibrated at 5 °C for 30 min, and placed in liquid nitrogen (LN₂) vapour for 15 min before being plunged into LN₂. After thawing, sperm samples were evaluated for motility and velocity variables, mitochondrial membrane potential, apoptosis, and plasma membrane and DNA integrities. For sperm motility variables, there were dose- and time-dependent effects, with the largest values recorded when 12.5 and 25 ng/mL relaxin were used for 0-120 min of incubation. Furthermore, at all of the concentrations at which there were evaluations, relaxin additions to semen diluent led to a marked improvement in sperm mitochondrial membrane potential and a lesser percentage of apoptotic cells compared to the control group. Plasma membranes and DNA integrities were not affected by relaxin supplementations to the diluent. In conclusion, supplementation of relaxin in extender before semen cryopreservation, especially at 12.5 and 25 ng/mL, had a positive effect on the sperm quality variables.

Sorting and cryopreservation of goat sperm with or without phenolic compounds

ABSTRACT The objectives of this study were to evaluate goat sperm sorting in continuous Percoll® density gradients and gamete freezability, in the presence or absence of phenolic antioxidants. For this, semen pools were sorted, frozen, and evaluated. The non-selected group (NSg) presented lower progressive motility (PM), linearity (LIN), straightness (STR), and wobble (WOB) than the selected groups, and straight line velocity (VSL) compared to those with catechin or resveratrol. The amplitude of lateral head displacement (ALH) was higher in NSg, and quercetin reduced the mitochondrial membrane potential (MMP). After thawing, the NSg presented lower PM than the selected groups, VSL and VAP (average path velocity) than the selected group with or without catechin, LIN and WOB than the selected with or without catechin or resveratrol, and STR than the selected with catechin. Moreover, NSg presented higher ALH and BCF than the samples selected with or without catechin. Plasma membrane integrity and intact and living cells were higher in the selected groups, and MMP was lower in the NSg and the selected group with quercetin. Thus, centrifugation in Percoll® continuous density gradients is a viable methodology to select goat sperm compatible with the freezing, especially in the presence of catechin or resveratrol.

Strategies to Minimize Various Stress-Related Freeze-Thaw Damages During Conventional Cryopreservation of Mammalian Spermatozoa

The aim of the article is to report a review on different sperm cryopreservation techniques, various stress-related freeze-thaw damages altering sperm structure and function during conventional cryopreservation, and strategies to minimize these stresses. Sperm cryopreservation has allowed indefinite storage and successful transportation of valuable germplasm from proven sites at distant locations, for genetic upgradation through implementation of reproductive techniques, such as artificial insemination. Different techniques for sperm cryopreservation have been proposed such as conventional freezing techniques, directional freezing, and sperm vitrification. Drawbacks related to conventional freezing methods, such as heterogeneous ice nucleation and repeated freeze-thaw cycles at the ice front that disrupts and kill sperm cells, led to the emergence of the directional freezing technique. Sperm vitrification is advantageous as there is no ice crystal-induced physical damages to sperm. However, sperm vitrification has less applicability as encouraging results are only reported in human, dog, and cat. In spite of several drawbacks, conventional freezing techniques are still most widely used for sperm cryopreservation. Spermatozoa experience stresses in the form of cold shock, osmotic stress, and mainly oxidative stress during conventional cryopreservation ultimately reduces the sperm viability and fertility. Several attempts have been made in the past to minimize all these stresses individually or in combination. Membrane fluidity was increased to prevent the cold shock and cryocapacitation-like changes by the addition of cholesterol to the membrane. Antifreeze proteins were added in semen extender to minimize freeze-thaw damages due to heterogeneous ice nucleation and ice recrystallization. Oxidative stress was reduced either by neutralizing reactive oxygen species (ROS) through enzymatic, nonenzymatic, plant-based antioxidants or reductants; or by minimizing the level of sources like the semen radiation exposure, leucocytes, and dead and defective spermatozoa, which lead to ROS production during the semen cryopreservation process. A novel approach of minimizing oxidative stress was to reduce the oxygen tension in sperm microenvironment that is, extender by partial deoxygenation process, as a number of literatures pointed out direct link of O₂ with ROS production. When compared with other strategies, partial deoxygenation of semen extender with N₂ gassing is found as a cost-effective, comparatively easy and a potential approach to large-scale frozen semen production.

Stimulating effects of Quercetin (QUE) in tris citric acid extender on post thaw quality and in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa

Aim of this study was to evaluate the stimulating effects of quercetin (QUE) on post thaw quality and in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa. QUE is a well-known flavonoid having antioxidant properties to scavenge free radicals. Semen was collected from three buffalo bull through artificial vagina (42 °C) and were evaluated initially for volume, motility, concentration, followed by dilution in five extenders (n = 5 aliquots, control, C = no QUE; treatment 1, T1 = 50 μM QUE; treatment 2, T2 = 100 μM QUE; treatment 3, T3 = 150 μM QUE and treatment 4, T4 = 200 μM QUE supplementation). The experiment was repeated thrice (n = 3 replicates). At post dilution, sperm progressive motility (PM, %) plasma membrane integrity (PMI, %), supra vital plasma membrane integrity (SVPMI, %) and acrosome integrity (ACR-1, %) of buffalo bull were significantly higher (P < 0.05) in extenders supplemented with QUE than C. At thawing, sperm PM of buffalo bull was higher in T3 and T4 than C, T1 and T2. Sperm SVPMI was significantly higher in T2, T3 and T4 than C and T1. Sperm ACR-I was higher in T3 and T4 than C, T1 and T2. Sperm DNA integrity was higher in T4 than C. QUE supplementation increased in vitro semen quality during 30 and 60 min of incubation at 37 °C than C. The in vivo fertility was higher in T3 and T4 than C (%, 61.82 vs. 65.22 vs. 46.90). It is concluded that QUE @ 150 and 200 μM improved post thaw semen quality and in vivo fertility of buffalo bull.

Quercetin attenuates H2 O2 -induced toxicity of rooster semen during liquid storage at 4°C

Current study was carried out to examine the protective effects of quercetin against toxicity induced by hydrogen peroxide in rooster semen in vitro. Semen samples were collected from ten roosters (Ross 308 broiler breeder males, 32 weeks old) twice a week by abdominal massage method. Samples with ≥70% progressive motility were selected, pooled, diluted and used for the study. Experimental groups consisted of negative control, control that received solvent of quercetin, H₂ O₂ (40 μM) and combination groups which incubated with constant dose of H₂ O₂ (40 μM) plus various levels of quercetin (20, 40 and 80 μM). Measurement of total hydroperoxide (HPO), malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (TAC) and superoxide dismutase activity as well as routine sperm tests were done at 0, 24 and 48 hr of storage at 4°C. Results revealed that exposure to hydrogen peroxide significantly increased HPO (138.43 ± 7.32 vs. 66.08 ± 3.97 μmol/g protein), MDA (7.21 ± 0.08 vs. 5.71 ± 2.16 μmol/g protein) and NO (0.367 ± 0.013 vs. 0.215 ± 0.011 μmol/g protein) levels and decreased sperm progressive motility (27.28 ± 1.21 vs. 47.49 ± 1.29%), and amounts of TAC (11.49 ± 0.39 vs. 15.70 ± 0.79 mmol/g protein) compared to control at 24 hr (p < 0.05). Changes at mentioned variables were repeated at 48 hr of storage. Also, co-administration of quercetin (especially at 40 and 80 μM) with hydrogen peroxide restored the toxic effects of hydrogen peroxide on rooster semen parameters such as primary and secondary lipid peroxidative indicators and other evaluated variables. The study concluded that rooster semen enrichment with quercetin would protect lipid peroxidative and nitrosative hydrogen peroxide-mediated damage during cold liquid storage of rooster semen.

Dimethyl sulfoxide and quercetin prolong the survival, motility, and fertility of cold-stored mouse sperm for 10 days

Technology for preserving sperm is useful for disseminating valuable male genetic traits. Cold storage is suitable for easily transporting sperm as an alternative to the shipment of live animals. However, there is a technical limitation in that the fertility of cold-stored sperm declines within 3 days. To overcome this problem, we examined the protective effects of quercetin and dimethyl sulfoxide (DMSO). DMSO and quercetin maintained the fertility and motility of cold-stored sperm for 10 days. In addition, quercetin attenuated the reduction of mitochondrial membrane potential of cold-stored sperm during sperm preincubation, allowing the induction of capacitation, and it localized to the midpiece of sperm. Furthermore, DMSO and quercetin enhanced the level of tyrosine phosphorylation of cold-stored sperm. DMSO and quercetin have life-prolonging effects on sperm during cold storage. Cold storage using DMSO and quercetin will provide a robust system for internationally transporting valuable sperm samples.

Comparing Human Sperm Quality Preserved at Two Different Temperatures; Effect of Trolox, Coenzyme Q10 and Extracellular Adenosine Triphosphate

Cooling method was proposed to maintain the sperm quality for several days. Nevertheless, during this procedure, sperm is encountered to "cold shock", and its quality decreases time-dependently. This study was designed to improve the in vitro sperm preservation methods. Thirty normal semen samples were examined in Shiraz, Iran, 2017. Fifteen samples were incubated at 22-27 °C and 15 samples were cooled moderately to 4 °C. Each sample was divided into five subgroups; control, solvent, 200 μM Trolox, 40 μM Coenzyme Q10, and 10 mM ATP. ATP was added only 15 minutes before the analysis. Assessments of motility parameters and sperm viability were done every 24 hours. Statistical analysis was performed using SPSS 16 software. The differences between two main groups and subgroups were compared by t test and one-way ANOVA, respectively. The effect of time was analyzed by repeated measurement test. Sperm motility and viability were the same in both groups until 24 hours, except the straight line velocity was greater in the cold group. Even after 48 hours, progressive motility and sperm velocity, but not viability, were still the same. The greatest reduction in progressive motility occurred on the second day; and after 72 hours, sperm quality was better preserved in 22-27 °C. Treatment with Trolox, coenzyme-Q10, and extracellular ATP did not have effect on sperm quality. Cold temperature is recommended for in-vitro sperm preservation up to 24 hours, and 22-27 °C is preferred for longer time storage. The sperm does not need antioxidant therapy for quality maintenance, but the extender media must be supplied with nutrients and antibiotics.

Isoespintanol improves the post-thaw quality of stallion semen

The present study was conducted to assess the effect of the egg yolk powder in place of fresh egg yolk (EY) in the semen diluent on semen morphological attributes (SMAs) and mobility & velocity profiles measured by computer assisted sperm analyser (CASA) in cryopreserved mithun semen. A total of 25 ejaculates were collected through rectal massage method from five healthy mithun bulls (five ejaculates in each bull) and diluted with the standard tris citrate glycerol (TCG) extender and were splited into four equal aliquots: Gr I: control (20% EY); Gr II, III and IV contained 5, 8 and 10% EY powder, respectively. SMAs, CASA parameters were evaluated following freezingthawing of semen. Result revealed significant (p<0.05) improvement was observed in these SMAs and CASA parameters in Gr II and III as compared to Gr I and IV. It was concluded that inclusion of 5% or 8% EY powder in semen diluent holds a clear advantage and higher benefits over 20% fresh EY in cryopreservation of mithun semen.

Supplementation of quercetin for advanced DNA integrity in bull semen cryopreservation

The aim of this study was to identify the effects of adding quercetin (Q) to Tris extender in order to identify levels of oxidative stress in bull sperm after freeze thawing. Ejaculates were collected via artificial vagina from Holstein bulls. Semen was divided into five tools and diluted to a final concentration of 15 × 106 spermatozoa/ml with the Tris extender containing Q (25, 50, 100 and 200 μg/ml) and no additive (control; C). All examples were equilibrated at 4°C during 4 hr then were loaded into 0.25-ml straws and frozen using a controlled rate. Sperm motility and motility characteristics were determined using the computer-assisted semen analyser. Sperm membrane integrity was assessed using the hypoosmotic swelling test. Sperm chromatin integrity was investigated using the single cell gel electrophoresis. Total antioxidant capacities were performed colorimetrically. Q supplementation used as an antioxidant did not produce better results in the proportion of sperm progressive and total motility, plasma membrane integrity and sperm abnormalities. Q supplementation exhibited the favourable tail length, tail DNA and tail moment. In conclusion, when whole parameters are considered, Q25 can be added to the Tris extender due to its positive effect on sperm DNA integrity and no adverse effect on the progressive and total motilities of sperm.

Reproduction biotechnologies in germplasm banking of livestock species: a review

Many biotechnologies are currently used in livestock breeding with the aim of improving reproductive efficiency and increasing the rate of genetic progress in production animals. Semen cryopreservation is the most widely used cryobiotechnology, although vitrification techniques now allow embryos and oocytes to be banked in ever-increasing numbers. Cryopreservation of other types of germplasm (reproductive tissue in general) is also possible, although the techniques are still in the early stages of development for use in livestock species. Although still in their infancy, these techniques are increasingly being used in aquaculture. Germplasm conservation enables reproductive tissues from both animals and fish to be preserved to generate offspring in the future without having to maintain large numbers of living populations of these species. However, such measures need careful planning and coordination. This review explains why the preservation of genetic diversity is needed for livestock and fish, and describes some of the issues involved in germplasm banking. Furthermore, some recent developments in semen handling leading to improved semen cryopreservation and biosecurity measures are also discussed.

Role of Antioxidants in Assisted Reproductive Techniques

Oxidative stress (OS) has been recognized as a significant cause of suboptimal assisted reproductive outcome. Many of the sperm preparation and manipulation procedures that are necessary in the in vitro environment can result in excessive production of reactive oxygen species (ROS) thereby exposing the gametes and growing embryos to significant oxidative damage. Antioxidants have long been utilized in the management of male subfertility as they can counterbalance the elevated levels of ROS inducing a high state of OS. Few studies have looked into the clinical effectiveness of antioxidants in patients undergoing assisted reproduction. While an overall favorable outcome has been perceived, the specific clinical indication and optimal antioxidant regimen remain unknown. The goal of our review is to explore the sources of ROS in the in vitro environment and provide a clinical scenario-based approach to identify the circumstances where antioxidant supplementation is most beneficial to enhance the outcome of assisted reproduction.

Epigallocatechin-3-gallate (EGCG) and green tea polyphenols do not improve stallion semen parameters during cooling at 4°C

Stallion semen storage for artificial insemination is mainly based on liquid cooled storage. In many stallions this technique maintains sperm quality for an extended period of time (24-72 hr) at 7°C. While this technique is commonly used in the horse industry, there can be a decline in fertility in some stallions, due to an inability of their sperm to tolerate the cool storage process. The aim of the present work was to evaluate the effect of two natural antioxidants (epigallocatechin-3-gallate (EGCG) at 20, 60 and 120 μm and green tea polyphenols, and p at .001, .01 and .1 mg/ml) on some sperm parameters (sperm motility, viability/acrosome integrity and DNA quality) in extended semen immediately after its collection (T0) and after 2, 6, 24 and 48 hr of cool storage. Two ejaculates from three trotter stallions were analysed after 48 hr of storage at 4°C. No beneficial effect on the analysed parameters was observed: the two antioxidants were not able to improve sperm quality after 48 hr of storage. These results are in agreement with previous findings on the effect of different antioxidants reported by other researches, who have demonstrated that stallion semen keeps good antioxidant capacity after dilution for 24 hr. In conclusion, the positive effect exerted by antioxidant molecules in other species is not confirmed in the equine one.

Analysis of the effects of polyphenols on human spermatozoa reveals unexpected impacts on mitochondrial membrane potential, oxidative stress and DNA integrity; implications for assisted reproductive technology

The need to protect human spermatozoa from oxidative stress during assisted reproductive technology, has prompted a detailed analysis of the impacts of phenolic compounds on the functional integrity of these cells. Investigation of 16 individual compounds revealed a surprising variety of negative effects including: (i) a loss of mitochondrial membrane potential (Δψm) via mechanisms that were not related to opening of the permeability transition pore but associated with a reduction in thiol expression, (ii) a decline in intracellular reduced glutathione, (iii) the stimulation of pro-oxidant activity including the induction of ROS generation from mitochondrial and non-mitochondrial sources, (iv) stimulation of lipid peroxidation, (v) the generation of oxidative DNA damage, and (vi) impaired sperm motility. For most of the polyphenolic compounds examined, the loss of motility was gradual and highly correlated with the induction of lipid peroxidation (r=0.889). The exception was gossypol, which induced a rapid loss of motility due to its inherent alkylating activity; one consequence of which was a marked reduction in carboxymethyl lysine expression on the sperm tail; a post-translational modification that is known to play a key role in the regulation of sperm movement. The only polyphenols that did not appear to have adverse effects on spermatozoa were resveratrol, genistein and THP at doses below 100μM. These compounds could, therefore, have some therapeutic potential in a clinical setting.

Human Sperm Quality and Metal Toxicants: Protective Effects of some Flavonoids on Male Reproductive Function

Background

Metals can cause male infertility through affection of spermatogenesis and sperm quality. Strong evidences confirm that male infertility in metal-exposed humans is mediated via various mechanisms such as production of reactive oxygen species (ROS). Flavonoids have antioxidant and metal chelating properties which make them suitable candidates for neutralizing adverse effects of metals on semen quality. In the current study, we have evaluated the effects of five types of flavonoids (rutin, naringin, kaempferol, quercetin, and catechin) on recovery of sperm motility and prevention of membrane oxidative damage from aluminum chloride (AlCl₃), cadmium chloride (CdCl₂), and lead chloride (PbCl₄).

Materials and Methods

In this experimental study, motility and lipid peroxidation of metalexposed sperm was investigated in the presence of different concentrations of five kinds of flavonoids. Malondialdehyde (MDA) production was assessed as a lipid peroxidation marker.

Results

Aluminum chloride (AlCl₃), cadmium chloride (CdCl₂), and lead chloride (PbCl₄) diminished sperm motility. Treatment of metal-exposed sperm with rutin, naringin, and kaempferol attenuated the negative effects of the metals on sperm motility. Quercetin and catechin decreased the motility of metal-exposed sperm.

Conclusion

Based on the MDA production results, only AlCl₃ significantly induced lipid peroxidation. Treatment with rutin, naringin, and kaempferol significantly decreased MDA production.

Field fertility of liquid stored and cryopreserved flow cytometrically sex-sorted stallion sperm

REASONS FOR PERFORMING STUDY

The fertility of sex-sorted, cryopreserved stallion sperm must be improved for the sex-sorting technology to be applied commercially.

OBJECTIVES

To optimise the conditions used to liquid store stallion sperm prior to sex-sorting and assess the fertility of sperm following sex-sorting and cryopreservation.

STUDY DESIGN

Both in vitro experiment and randomised controlled trial in healthy, client-owned mares.

METHODS

Stallion ejaculates (n = 9) were diluted in either a skimmed milk (KMT) or BSA (I-BSA) based media to 25 × 10⁶ sperm/ml directly (+SP25) or washed to remove seminal plasma and diluted to 25 or 111 × 10⁶ sperm/ml (-SP25 and -SP111). Sperm were stored for 18 h at 10 to 15°C and -SP25 and +SP25 treatments were centrifuged and resuspended to 111 × 10⁶ sperm/ml. Sperm were incubated under H33342 staining conditions and motility, viability and acrosome integrity assessed. Semen was collected from stallions (n = 4), liquid stored at 10-15°C for up to 5 h and sperm either cryopreserved directly, sex-sorted and cryopreserved, or sex-sorted and returned to liquid storage until insemination. Low-dose hysteroscopic insemination was performed in 23 mares randomly allocated to the semen preparation group and pregnancy determined following embryo flushing on Day 9 after ovulation, or via transrectal ultrasonography on Day 14 after ovulation.

RESULTS

Skimmed milk was superior to I-BSA in maintaining motility, viability and acrosome integrity. Seminal plasma removal did not affect the parameters measured at the concentrations examined. Conception rates did not differ significantly between the groups, although a high incidence of pregnancy loss was observed in both the cryopreserved groups.

CONCLUSIONS

While the conception rates achieved are among the highest yet reported for sex-sorted, cryopreserved stallion sperm, the high incidence of pregnancy loss suggests that the development of the resulting embryos was significantly impaired by the sperm processing treatments.

Effect of Quercetin-loaded liposomes on induced oxidative stress in human spermatozoa

A strategy to circumvent the poor polyphenols bioavailability is to load these compounds into liposomes. We evaluated the in vitro effects of quercetin (Q) and Q-loaded liposomes (QLL, 30, 50, 100μM) on motility, viability and chromatin integrity of swim-up selected human sperm. Antioxidant power was assayed against tert-butylhydroperoxide induced lipid peroxidation (LPO) using C11-BODIPY581/591 fluorescent probe and transmission electron microscopy. QLL showed decreased toxicity for sperm motility and viability and increased DNA damage compared to Q. The percentage of sperm with fluorescence, marker of LPO, was decreased in samples incubated with Q vs QLL (P<0.001). The ultrastructure of acrosomes and membranes was preserved with Q 30/100μM, whereas QLL did not prevent membrane injury. Q alone appeared more effective than Q incorporated into liposomes; however liposomes could be considered as carriers that may convey different compounds inside sperm; they may therefore represent a field of research rich of many applications.