Effect of taxifolin on cold-shock damages in spermatozoa in rabbits

Objective: To investigate the effect of taxifolin added to rabbit semen on freezing-induced cold-shock damages in spermatozoa. Methods: Semen was collected from six adult New Zealand rabbits once a week by artificial vagina. The collected semen was pooled at 38 °C and divided into four equal volumes. They were diluted with 0, 50, 100 and 200 μM taxifolin-containing Tris + egg yolk extender at 38 °C and their temperatures were lowered to 4 °C. Following equilibration, semen drawn into 0.25 mL straws were frozen in an automatic semen freezing device and stored in liquid nitrogen container at -196 °C. Samples were thawed in 38 °C water for 25 s and the analyses of motility, kinematic parameters, morphological deformities, changes in membrane integrity, mitochondrial membrane potential, dead-live ratio, acrosomal damages and as well as oxidative stress analyses were performed in semen. Results: Addition of 50 μM taxifolin significantly improved motility (total, progressive, rapid and static), high mitochondrial membrane potential and the ratios of spermatozoa with acrosomal damage compared to the control group. Compared to the control group, malondialdehyde (MDA) levels in the 50 and 100 μM taxifolin groups were significantly lower, while the MDA level was high and viable spermatozoa ratio was low in the 200 μM taxifolin group. There were no significant differences between the groups in terms of kinematic parameters, morphological deformities, membrane integrity and antioxidant levels. Conclusions: The low dose of taxifolin (50 μM) has a positive effect and the high dose (200 μM) has a negative effect. Therefore, it is concluded that the addition of low-dose (50 μM) taxifolin to the extenders would be a useful additive in reducing cold-shock damage that occurs during freezing of rabbit semen.