Differential effects of polysulphates between mouse and hamster during in vitro fertilization

The interaction between zona pellucida polysulphates and sperm receptors appears to be a widespread mechanism used by mammals during gamete interaction. In this work, the effect of heparin on binding, penetration and fertilization of mouse and hamster oocytes was assessed. We found that heparin inhibited oocyte penetration and fertilization in both species. Heparin as well as fucoidan (a fucose-sulphate polymer) inhibited the proteolytic activity of acrosomal enzymes in both species. Our results suggest that zona pellucida penetration in both species may be modulated by polysulphates acting on either the proteolytic rate of degradation of the zona and/or its interaction with acrosome-reacted sperm (secondary binding).