Effect of insulin and leptin on ram sperm capacitation for in vitro embryo production

Improvement of sperm quality as a research field in reproductive biotechnology of domestic animal can be considered as a key element for in vitro fertilization. The aim of the present study was to investigate the effects of insulin and leptin on ovine sperm capacitation / acrosomal reaction, viability and fertilization. The semen samples of 10 Bakhtiari rams were collected by artificial vagina. Using dose response study, the most efficient doses of insulin and leptin were chosen. Each sample was assigned to four experimental groups including insulin (1nM), leptin (100nM), mixed of leptin-insulin and control (without hormone). Sperm capacitation/acrosomal reaction, viability and fertilization were evaluated by chlortetracycline staining, eosin-negrosin and in-vitro fertilization methods, respectively. values were compared among groups by 1-way ANOVA. Values of capacitation/ acrosomal reaction rate showed significant increase in response to insulin and leptin at 30, 60 and 120 min time points. The sperm viability was significantly (p<0.05) increased in response to insulin when compared with the control group at 30 min time point, without any effect in the other time points. On the other hand, insulin and leptin did not show significant effect (p>0.05) on sperm fertilization. This study indicated that insulin and leptin improved ram sperm capacitation / acrosomal reaction and viability while their effects on in vitro embryo production were inconsiderable.