Effect of Zinc on Decondensation of Human Spermatozoa Nuclei by Heparin

Abstract

Swelling sperm nuclei were assayed, exposing them to the combine action of heparin in increasing amounts of seminal plasma 0.1-1.0 ml (124 .+-. 21 .mu.g of Zn2+/ml). An inhibition of almost 30% in the swollen spermatozoa nuclei was observed with 0.1 ml of seminal plasma (12 .mu.g of Zn2+/ml) reaching to 71% with 74-124 .mu.g of Zn2+/ml. Inactivated seminal plasma (boiling) induced the same percentage of inhibition (73%) than normal seminal plasma. Dialyzed seminal plasma (31 .mu.g of Zn2+/ml) produced an inhibition of 88% of swollen spermatozoa nuclei, the same percentage produced with 30-35 .mu.g of Zn ions (ZnCl2). Previous release of sperm Zn by preincubation with EDTA 6 mM changed the decondensation kinetics, making sperm nuclei more susceptible to the action of the glycosaminoglycan. No effect was observed in the presence of Ca ions. Zn, among its several physiological roles, may act as a nuclear chromatin stabilizer.