Studies on the membrane integrity of human sperm treated with a new injectable male contraceptive

BACKGROUND: The aim of this study was to evaluate the integrity of sperm surface characteristics in the presence of a new male contraceptive, RISUG [1 mg styrene maleic anhydride (SMA)/100 μl dimethylsulphoxide (DMSO) in 1 ml sperm solution]. METHODS: Progressively motile human sperm were treated in vitro with RISUG. The cells were analysed for the release of 5′-nucleotidase (5′-NT) (a plasma membrane marker) using 3 mmol/l 5′-AMP and 3 mmol/l β-glycerophosphate as substrates. Hyaluronidase (an acrosomal membrane marker) was analysed using hyaluronic acid as a substrate. The contents of free and total acrosin, and % proacrosin (all acrosome markers) were assayed using 0.5 mmol/l α-N-benzoyl-L-arginine ethylester (BAEE). RESULTS: RISUG caused almost complete disintegration of the plasma membrane leading to significant (P