Topological alterations in human spermatozoa associated with the polyelectrolytic effect of RISUG®

A new method of male contraception has been developed which results in long-term infertility and has the potential advantage of being reversible. The contraceptive, given the name RISUG® (an acronym for Reversible Inhibition of Sperm Under Guidance) is a polyelectrolytic compound and when injected into the lumen of the vas deferens, induces a surface charge imbalance on the sperm membrane system leading to its destabilization. In the present study, morphological and topological alterations in human spermatozoa induced by RISUG® have been investigated using atomic force microscopy (AFM). Complete disintegration of the plasma membrane with subsequent rupture and dispersion of the acrosomal contents is observed on treatment with RISUG® in vitro. Considerable damage to the midpiece region with significant clustering of the mitochondria and its fusion with the head region is also observed. These observations are in agreement with the significant increase in the volume of RISUG®-treated sperm-head region. Topological alterations in the flagellar and midpiece region of RISUG®-treated spermatozoa have also been studied.