Glass transition temperature (Tg) as a measure of sperm fertility: Effect of antifertility drug nifedipine and its analogues

Contraception being the need of the hour, we have synthesized a few analogues of nifedipine, an L-type calcium channel blocker and evaluated their effects on sperm fertility. The glass transition temperature (Tg) of spermatozoa has been monitored using DSC to characterize the cellular damage due to aging or by external agents. In this paper we report how Tg can be used as a marker to measure infertility caused by external agents. The cellular damage can be due to the cell immobilization or due to the membrane alteration eventually leading to infertility. Results have been supported by measuring the cell motility, metabolism and lipid peroxidation; the well established markers for estimating the sperm fertility. Unlike D4, nifedipine and analogue D2 cause sperm cell aging by hampering the motility without causing the membrane damage. This indicates that the damage caused due to D4 may be irreversible. Thus the present findings demonstrate that D2 can be a promising candidate as a lead molecule for the development of reversible antifertility agents.