Different effects of cGMP and cAMP analogs on kinematic parameters of ram epididymal sperm in vitro

摘要

The present study investigated the effects of exogenous cyclic GMP (cGMP) and cyclic AMP (cAMP) on kinematic parameters of epididymal ram sperm in vitro. After incubation of epididymal sperm samples for 45 and 90 min in the presence of 8-Br-cAMP (0.1, 1, and 5 mM) and 8-Br-cGMP (0.05, 0.5, and 5 mM), motion parameters were evaluated by computer-aided sperm analysis. At 0.1 mM concentration of 8-Br-cAMP, there was a significant increase in the fast progressive motility (at 45 min), nonpro-gressive motility (at 90 min), amplitude of lateral head displacement (ALH; at 45 min), curvilinear velocity (VCL; at 90 min), and mean angle of deviation (MAD; at 90 min) of sperm while a decrease in the immotility and beat cross frequency (BCF; at 45 and 90 min) in cAMP-treated groups was observed. At 1 mM of 8-Br-cAMP, there was a significant increase in the fast progressive motility (at 45 min), nonpro-gressive motility (at 90 min), VCL (at 45 and 90 min), straight line velocity (VSL), average path velocity (VAP), MAD, ALH, linearity (LIN), and straightness (STR; at 45 min) of sperm but decreasing immotility, BCF (at 45 and 90 min) and wobble (at 90 min) in cAMP-treated groups compared to controls. At 5 mM of 8-Br-cAMP, a significant elevation in the immotility and BCF of sperm was observed while reductions in the fast progressive motility, VCL,VSL, VAP, MAD, ALH, STR, and LIN was noted in the cAMP-treated groups at 45 and 90 min of incubation. The effects of 8-Br-cGMP on sperm motility were not significant. In conclusion, low concentrations of exogenous cAMP but no cGMP improves the motion parameters of ram epididymal sperm.