ABSTRACT
Background: intracellular calcium and proton concentrations are important factors for activating human sperm. Calcium ion [Ca2+] enters sperm through voltagedependent calcium channel of sperm [CatSper]. Proton was extruded from sperm through voltage-gated proton channel [Hv1]. In the present study, the selective inhibitors of the CatSper and Hv1 channels, NNC 55-0396 [NNC] and zinc ion, respectively, were used to investigate functions of these channels
Methods: normal semen samples [n=24] were washed and diluted to 20×106 sperm/ ml. The diluted sample was divided into 8 groups, containing Ham's F-10 [the control group], 2 microM NNC, 1 mM ZnCl2 and NNC+Zn. The other 4 groups were the same as above, except that they contained 1 microM progesterone. The computer assisted analysis was done by VT-Sperm 3.1 to determine the percentage of motile sperm and sperm velocity. Acrosomal status was monitored by FITC-PSA and viability assessed by Eosin-Y staining. Statistical comparisons were made using ANOVA followed by Tukey post hoc test. The p<0.05 was considered significant
Results: the percentage of viable and motile sperm, curvilinear velocity and other parameters of motility was reduced in all groups containing NNC, zinc and NNC+ zinc. Progesterone-induced acrosome reaction was abolished by each of these inhibitors. The combination effect of NNC plus zinc on motility and progesterone-induced acrosome reaction was not stronger than NNC by itself
Conclusion: catsper and Hv1 channels play a critical role in human sperm function and viability. It seems that a functional relationship exists between CatSper and Hv1 channels