Cysteine protects rabbit spermatozoa against reactive oxygen species-induced damages

Abstract

The process of cryopreservation results in over-production of reactive oxygen species, which is extremely detrimental to spermatozoa. The aim of this study was to investigate whether addition of cysteine to freezing extender would facilitate the cryosurvival of rabbit spermatozoa, and if so, how cysteine protects spermatozoa from cryodamages. Freshly ejaculated semen was diluted with Tris-citrate-glucose extender supplemented with different concentrations of cysteine. The motility, intact acrosomes, membrane integrity, mitochondrial potentials, 8-hydroxyguanosine level and sperm-zona pellucida binding capacity were examined. Furthermore, glutathione peroxidase (GPx) activity, glutathione content (GSH), and level of reactive oxygen species (ROS) and hydrogen peroxide of spermatozoa were analyzed. The values of motility, intact acrosomes, membrane integrity, mitochondrial potentials and sperm-zona pellucida binding capacity of the frozen-thawed spermatozoa in the treatment of cysteine were significantly higher than those of the control. Addition of cysteine to extenders improved the GPx activity and GSH content of spermatozoa, while lowered the ROS, DNA oxidative alterations and lipid peroxidation level, which makes spermatozoa avoid ROS to attack DNA, the plasma membrane and mitochondria. In conclusion, cysteine protects spermatozoa against ROS-induced damages during cryopreservation and post-thaw incubation. Addition of cysteine is recommended to facilitate the improvement of semen preservation for the rabbit breeding industry.

Notoginsenoside R1 protects boar sperm during liquid storage at 17°C

“…There were significant differences in the number of spermatozoa bound to ZP at day 7 between the control and 50 μM NR1 groups during liquid storage at 17°C. Zhu et al have demonstrated that cysteine significantly enhances the ZP binding capacity of frozen‐thawed spermatozoa in rabbits, which are similar to our results (Zhu et al., 2017). AI fertility parameters are the most important factors for assessing spermatozoa quality.…”

Sperm Antioxidant Biomarkers and Their Correlation with Clinical Condition and Lifestyle with Regard to Male Reproductive Potential

“…Several studies demonstrated that the addition of GSH to cryopreserved ejaculate of animals protects the sperm from the harmful effects of ROS accumulated during this process, at the same time improving sperm motility, viability, the integrity of the cell membrane, and sperm DNA, as well as the activity of antioxidant enzymes [ 50 , 51 , 52 ]. The addition of cysteine to rabbit ejaculate increased biosynthesis of intracellular glutathione and significantly affected cell membrane integrity, acrosomal inviolability or sperm motility [ 53 ]. The result of GSH meta-analysis is statistically significant ( p < 0.001), so evidence was found for differences between the groups.…”

Proline Protects Boar Sperm against Oxidative Stress through Proline Dehydrogenase-Mediated Metabolism and the Amine Structure of Pyrrolidine

“…According to Zhu et al [ 29 , 40 ], the LIVE/DEAD™ Sperm Viability Kit (Invitrogen™, Shanghai, China) and fluoresce isothiocyanate-peanut agglutinin (FITC-PNA) were used for the evaluation of membrane integrity and acrosome integrity, respectively. Sperm samples were incubated with SYBR working solution (100 nM) at 37 °C for 5 min and then with PI (propidium iodide) working solution (12 μM) for another 5 min for the detection of membrane integrity.…”

“…Growing evidence has demonstrated that ROS accumulates during the cooling and freezing-thawing process [ 29 ]. Addition of proline to semen extender significantly improved donkey sperm motility after cold storage at 5 °C for three days [ 30 ].…”