The Effect of Canthaxanthin on the Quality of Frozen Ram Spermatozoa

Effect of antifreeze protein type III on frozen/thawed of spermatozoa recover from goat epididymis

The objective of this study was to evaluate the effect of antifreeze protein type III (AFP III) on the freezing of epididymal spermatozoa of goats. A total of 16 pairs of testicles were collected in a slaughterhouse and transported at approximately 5 °C in a thermal box. Epididymal spermatozoa were recovered by retrograde lavage and evaluated using a phase contrast microscope. Then, they were cryopreserved in extender based on Tris-egg yolk, supplemented with AFP III (0, 1, 10, 100 μg/mL), using an automated system. After thawing (37 °C/30 s), the spermatozoa kinetics were evaluated using the CASA automated system; and plasma and acrosome membrane integrity, mitochondrial membrane potential, and intracellular ROS production, by flow cytometry. There was no difference (P ≥ 0.05) between the experimental groups for the parameters of spermatozoa kinetics, mitochondrial membrane potential, and ROS production. However, the integrity of plasma and acrosome membranes of frozen spermatozoa with 100 μg/mL of AFP III was lower (P < 0.05) than the control group. It was concluded that the addition of AFP III to the Tris-egg yolk extender, used in the freezing of sperm obtained from the epididymis of goats, did not improve the preservation of these cells.

Cyanidin-3-Ο-glucoside supplementation in cryopreservation medium improves human sperm quality

Currently, the cryopreservation of human spermatozoa must overcome the adverse effects of excessive oxidation. In this study, we aimed to evaluate the effect of supplementation of cryopreservation medium with cyanidin-3-Ο-glucoside (C3G) on sperm quality. Semen samples were obtained from men with normozoospermia according to WHO criteria (n = 39). The sperm parameter values were compared after cryopreservation in medium supplemented with and without C3G.Compared with the control group (without additive), low doses (50 μM and 100 μM) of C3G improved sperm viability and motility and decreased the reactive oxygen species (ROS) of spermatozoa, while high doses (200 μM) of C3G did not obviously enhance sperm quality. The amount of DNA fragmentation index (DFI) and high DNA stainability (HDS) after freezing were higher in the control group than in the C3G supplementation groups. Low-concentration C3G supplementation (50 μM) was negatively correlated with sperm ROS levels (r = -0.2, p = 0.03). Collectively, our findings suggest that C3G could be an efficient semen cryoprotectant that ameliorates oxidative stress in human sperm during cryopreservation.

Melatonin and canthaxanthin enhances sperm viability and protect ram spermatozoa from oxidative stress during liquid storage at 4°C

Antioxidants are used to minimize oxidative stress during liquid semen storage. The main aim of current study was to elucidate effect of supplementing melatonin and canthaxanthin in Tris-based extender could enhance seminal quality of ram at 4°C up to 72 h. A total of 48 ejaculates were collected from breeding Magra rams (n = 8) and were preliminarily subjected for various macroscopic and microscopic semen evaluation tests. These ejaculates were pooled and divided into three equal aliquots. Two aliquots were diluted (1:10) using extender encompassing final concentration of 1mM melatonin and 25 µM canthaxanthin and stored at 4°C. Third aliquot with extender only was kept as control. Structural and functional seminal changes were observed at different time points of preservation. Results revealed that mean values for progressive sperm motility, viability and total antioxidant capacity were significantly higher (p < 0.05) in melatonin group while hypo-osmotic swelling test was significantly (p < 0.05) higher in canthaxanthin group. Total sperm abnormalities and malondialdehyde levels were significantly (p < 0.05) lower in both treatment groups indicating their antioxidant efficacy in protection of spermatozoa from oxidative stress. Results of study indicated that supplementation of these antioxidants to ram semen could be used to enhance storage life of liquid semen at 4°C up to 72 h.

Effect of Hydrated Carbon 60 Fullerene on Frozen Ram Semen Quality

The aim of this study was to evaluate the effect of hydrated carbon 60 fullerene (C₆₀HyFn) on ram semen quality during cryopreservation. Three ejaculates from each of seven Akkaraman rams were collected using an artificial vagina during the nonbreeding season and pooled. Pooled semen samples were divided into 10 equal parts and diluted with tris + egg yolk extender not containing (control) and containing 100, 200, 400, and 800 nM and 1, 5, 10, 20, and 40 μM C₆₀HyFn at 37°C. After addition of 5% glycerol and an equilibration process for 3 hours, the samples were frozen in 0.25-mL straws in an automatic freezing device at -140°C and stored in a liquid nitrogen container. Straws were thawed 24 hours after freezing and analyzed immediately with no incubation period. Motility, kinematic parameters, abnormality, vitality, hypo-osmotic swelling test (HOST), and oxidative stress levels were analyzed in thawed semen. Compared with the control, 200, 400, and 800 nM and 1 and 5 μM C₆₀HyFn doses increased motility and HOST values and decreased the dead sperm rate. When compared with the control, addition of C₆₀HyFn significantly decreased malondialdehyde levels (between 200 nM and 40 μM doses) and significantly increased glutathione peroxidase (between 800 nM and 40 μM doses) and catalase (between 1 and 40 μM doses) activities. In conclusion, results of this study show that the C₆₀HyFn nanoparticles are nontoxic to ram semen and their supplementation in the extender is beneficial to sperm motility and membrane integrity after freeze-thawing.

Effects of L-Carnitine on Equine Semen Quality During Liquid Storage

l-Carnitine (LC) plays a key role in sperm metabolism, easily providing energy through β-oxidation, which positively affects motility. The objective of this study was to investigate the association between blood plasma and seminal plasma LC levels, as well as the effect of LC as an additive in a skimmed milk-based extender during sperm storage at 5°C. In the first experiment, semen and blood samples from 14 Quarter Horse stallions were used. The LC content in blood plasma and seminal plasma was determined by spectrophotometry and their relationships with seminal parameters were evaluated. In the second experiment, ejaculates (n = 16) from four Quarter Horses were used. Each ejaculate was split into four treatment groups with different LC concentrations: 0 (control), 0.5, 1.0, and 2.0 mM. Sperm motility, integrity of plasma and acrosomal membranes, intracellular reactive oxygen species content, and plasma membrane stability were evaluated immediately after samples reached 5°C (0 hour) and after 24, 48, and 72 hours. There was a positive correlation (p < 0.05) between LC levels in seminal plasma with both sperm concentration and plasma and acrosomal membrane integrity. Furthermore, the addition of LC (1 and 2 mM) preserved the motility of equine sperm stored at 5°C. It was concluded that the concentrations of LC with seminal plasma present correlate to semen parameters and the addition of LC to skimmed milk-based extender preserves the motility of equine sperm stored at 5°C for up to 48 hours.

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.

Canthaxanthin protects human sperm parameters during cryopreservation

Different antioxidants have been introduced to reduce oxidative stress during the cryopreservation. The main goal of this study was to evaluate the effects of canthaxanthin on human sperm parameters during the freeze-thaw process. This study was performed on 25 normozoospermic semen samples dividing into five groups including 0, 0.1, 1, 10, and 25 µM of canthaxanthin. The prepared spermatozoa were cryopreserved by rapid freezing technique. Sperm motility, viability (eosin-nigrosin), morphology (Papanicolaou), acrosome reaction (double staining), DNA denaturation (acridine orange), chromatin packaging (aniline blue and toluidine blue), and DNA fragmentation (sperm chromatin dispersion test) were evaluated before freezing and after thawing. All sperm parameters after thawing significantly were decreased compared to before freezing. Twenty-five micromolar canthaxanthin could significantly improve the progressive and total motility, viability, normal morphology, chromatin packaging, acrosome integrity and DNA denaturation and fragmentation. Ten micromolar canthaxanthin significantly improved total motility, viability, normal morphology, chromatin packaging, acrosome integrity and DNA denaturation and fragmentation. Whereas, in 1 µM group, there were significant differences only in improvement of acrosome integrity, chromatin packaging (toluidine blue) and DNA denaturation and fragmentation. But, in 0.1 µM group, there were no significant differences in any of measured parameters. It seems that canthaxanthin ameliorates detrimental effects of cryopreservation on human sperm parameters.