Caprine cauda epididymal sperm motility pattern in the capacitation medium supplemented with leptin

Abstract

Leptin is an adipocyte-derived hormone with a role in the reproductive system through metabolic signals. Studies have suggested that binding of leptin to its receptors which have been found in human and boar sperm activates biochemical pathways leading to sperm capacitation. The present study was designed to explore the effects of leptin on sperm kinetic pattern during capacitation in vitro. Epididymal spermatozoa were obtained from 30 adult goat testes in six replicates and incubated in capacitation medium (Ca2+-free Tyrode’s medium, Sperm-TALP) supplemented with 0 (Con, control group), 10 and 100 ng/mL (L10 and L100 groups, respectively). Motion parameters were assessed using computer-assisted sperm analysis system at 10, 30, 60, 120 and 240 min after sperm incubation at 37°C and 6 % CO2. Exposure of spermatozoa to two different doses of leptin caused a significant increase (p < 0.05) in total and progressive sperm motility, curvilinear and straight line velocity, linearity (Lin), mean angular displacement, amplitude of lateral head displacement (ALH) and beat cross-frequency (BCF) compared to the control group specially up to 60 min. There was not any significant difference between L10 and L100 groups in the evaluated parameters except for the first 10 min that L100 had better result in increasing Lin, ALH and BCF (p < 0.05) and at the time of 240 min in which L10 showed a significant increase in all motion parameters. In conclusion, this study showed that leptin supplementation had significant effects on sperm motility patterns and so could enhance the sperm capacitation process.