Effects of astaxanthin supplementation on the freezability, lipid peroxidation, antioxidant enzyme activities and post-thawing fertility of ram semen

Effects of organic and inorganic selenium supplementation on frozen-thawed ram semen at two cooling periods

The aim of this study was to evaluate the effects of different selenium compounds on the sperm quality of cryopreserved ram semen. Ejaculates from four rams, collected using an artificial vagina heated to 38 °C, were individually evaluated. The approved ejaculates were pooled and diluted (1:1 v:v) in Tris-egg yolk extender (20%, v/v) and separated into two control groups, one cooled for 2 h and the other for 4 h. The pooled ejaculates at the two cooling periods were supplemented with two doses (0.5 and 1 μg/mL) of organic selenium (ORG), and inorganic selenium (SeNa), each. The samples were packed in 0.25 ml straws, at a concentration of 400 × 106 sperms/mL and stored in liquid nitrogen. The straws were thawed in a water bath at 37 °C for 20 s, and the samples were subjected to sperm kinetics evaluation by Computer Assisted Semen Analysis software. Sperm membrane integrity, acrosome morphology, and mitochondrial potential were assessed. In addition, oxidative stress markers reactive oxygen species (ROS), ferric reducing antioxidant power (FRAP), thiobarbituric acid reactive species (TBARS), and glutathione peroxidase (GPx) enzyme activity) were also evaluated. No significant improvement was observed in the ram semen quality at the two cooling times. Supplementation of the freezing extender with 0.5 μg/mL ORG, subjected to 4 h cooling period, increased the sperm motility when compared with the control group at the same cooling time. In addition, the 0.5 μg/mL SeNa group, under the 2 h cooling period, showed an increase in sperm motility when compared to the control group at the same cooling period. Considering the importance of sperm motility as a fertility parameter, our study indicates that supplementation with ORG and SeNa can help improve the total motility of the cryopreserved ram semen.

Astaxanthin Improved the Quality of Hu Ram Semen by Increasing the Antioxidant Capacity and Mitochondrial Potential and Mitigating Free Radicals-Induced Oxidative Damage

The objective of this research was to investigate the effect of astaxanthin supplementations of semen extender on the quality of Hu ram semen after up to five days of preservation at 4 °C. Semen samples were collected from five healthy Hu rams using an artificial vagina during breeding season (April to August 2023) and diluted with a basic extender supplemented with control (0), 1 µM, 2 µM, 3.5 µM, or 4.5 µM of AXT. Overall, 170 semen ejaculate samples (34 repetitions) from five healthy Hu rams were used in our research study. The results revealed that the addition of AXT (3.5 µM) significantly (p ≤ 0.05) increased the sperm kinematic indexes (T.M%, P.M%, MAD%, STR%, and LIN %), sperm viability, plasma membrane integrity, acrosome integrity, total antioxidant content (T-AOC), and mitochondrial membrane potential (MMP) of the Hu rams spermatozoa after up to five days of preservation at 4 °C. Contrary to that, the addition of the best concentration of AXT (3.5 µM) to the semen extender significantly (p ≤ 0.05) reduced the reactive oxygen species (ROS) and malondialdehyde (MDA) concentration of Hu ram semen. In conclusion, the results of the current study indicate that the addition of a semen extender with AXT improves the quality of Hu ram spermatozoa by increasing the total antioxidant capacity (T-AOC) and mitochondrial membrane potential (MMP). On the other hand, reducing free radicals induced oxidative (ROS) and per oxidative (MDA) damage to Hu ram semen.

Ameliorative effect of crocin on post-thaw quality, fertility-associated gene expression and fertilization potential of buffalo (Bubalus bubalis) bull sperm

Buffalo bull sperm suffer more cryoinjuries due to lipid peroxidation of high structural polyunsaturated fatty acid contents than cattle sperm. Consequently, the post-thaw fertilization potential of buffalo bull sperm is compromised. Crocin is a carotenoid known for its antioxidant potential through scavenging reactive oxygen species. Objectives of the current study were to investigate the effect of crocin addition in the semen extender on post-thaw quality, fertility-associated gene expression and fertilization potential of buffalo bull sperm. Semen samples (n = 32) from four Nili-Ravi buffalo bulls were extended with tris-citric acid extender containing different concentrations of crocin (0 mM; control, 0.5, 1, 1.5 and 2 mM). The extended semen was packed in 0.5 mL French straws (25 × 106 sperm/straw) and cryopreserved in liquid nitrogen. Computer-assisted semen analysis, hypo-osmotic swelling test, normal apical ridge assay, Rhodamine 123, acridine orange, propidium iodide staining, and thiobarbituric acid reactive substances assay were performed to assess sperm motility parameters, plasma membrane integrity, acrosome integrity, mitochondrial membrane potential, DNA integrity, viability, and lipid peroxidation, respectively. Expression levels of sperm acrosome-associated SPACA3, DNA condensation-related PRM1, anti-apoptotic BCL2, pro-apoptotic BAX, and oxidative stress-associated ROMO1 genes were evaluated through qPCR. The fertility of semen doses containing the most potent concentration of crocin (based on optimum post-thaw semen quality) was compared with control during the breeding season. Buffaloes (n = 400; 200/group) were inseminated 24 h after the onset of oestrus and transrectally palpated for pregnancy at least 60 days post-insemination. Results revealed that 0.5 and 1 mM crocin improved sperm post-thaw total motility, plasma membrane integrity, acrosome integrity, mitochondrial membrane potential and viability, and 1 and 1.5 mM crocin enhanced catalase activity and reduced lipid peroxidation compared to control (p < .05). Moreover, 1 mM crocin improved sperm post-thaw progressive motility, kinematics, and DNA integrity, and 1.5 mM crocin enhanced plasma membrane integrity than control (p < .05). Expression levels of SPACA3, PRM1 and BCL2 genes were higher (p < .05) with 1 mM crocin compared to other groups. In contrast, no difference (p > .05) was noticed in expressions of BAX and ROMO1 genes among all groups. The fertility rate of semen doses containing the most potent concentration (1 mM) of crocin was higher (p = .0465) compared to control (56 ± 0.03% vs. 46 ± 0.04%, respectively). In conclusion, 1 mM crocin in the semen extender improves post-thaw quality, fertility-associated gene expression and fertilization potential of buffalo bull sperm.

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.

The Effect of Astaxanthin on Motility, Viability, Reactive Oxygen Species, Apoptosis, and Lipid Peroxidation of Human Spermatozoa During the Freezing-Thawing Process

Cryopreservation of spermatozoa is a general procedure to preserve viable sperm for an indefinite period. Despite the efficiency of sperm cryopreservation, excessive reactive oxygen species (ROS) production during cryopreservation can induce structural and functional changes in spermatozoa. Also, cryopreservation has been shown to decrease the spermatozoa's antioxidant activity inducing them to be more sensitive to damage caused by ROS. Experimental evidence suggests that astaxanthin (AXT) has essential activities such as antioxidant, antibacterial, and antithrombotic properties. Therefore, this study aimed to evaluate the effect of AXT on the sperm quality of healthy men during freezing-thawing. In the first phase, 10 semen samples with different concentrations of AXT (0.0, 0.5, 1, and 2 μM) were cryopreserved to achieve an optimal dose of AXT. Then, motility, viability, and phosphatidylserine (PS) externalization were evaluated. In the second phase, 25 samples were collected and divided into 3 groups: fresh group, control group (untreated frozen-thawed samples), and AXT group (treated frozen-thawed with AXT). Then, samples were cryopreserved in freezing media supplemented with or without the optimal concentration of AXT (1 μM). After thawing, the levels of sperm parameters, including motility (using a computer-assisted sperm analyzer), viability (eosin-nigrosin), early apoptotic change (annexin V/propidium iodide), ROS (flow cytometry), and lipid peroxidation (LPO) (using enzyme-linked immunosorbent assay), were evaluated. Our results showed that the addition of 1 μM AXT to sperm freezing media improved all parameters of sperm motility and viability (p ≤ 0.05). Furthermore, it could reduce the levels of ROS parameters (intracellular hydrogen peroxide and superoxide) compared with the control group (p ≤ 0.05). Also, AXT significantly decreased the level of PS externalization (p ≤ 0.05) and LPO (p ≤ 0.05) after the freezing-thawing process. In conclusion, our findings demonstrated that human semen treatment with 1 μM AXT before the freezing-thawing process has protective effects against oxidative stress and could diminish the destructive effects of this process on sperm quality.

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.