Gelatin-substrate film technique for detection of acrosin in single mammalian sperm.

Sperm acrosin proteolytic activity in single sperm can be detected by a protein-free halo on a gelatin-substrate film. With current techniques, halos have variable sizes and are often absent because of unevenness of the hand-spread gelatin-substrate film. We prepared gelatin-substrate films with a coating machine. Using these films, halos were formed uniformly throughout the gelatin-substrate films in the vicinity of single mammalian sperm. The level of acrosin activity as determined by halo diameters was human greater than dog greater than squirrel monkey greater than mouse greater than rat. This simple and reproducible technique may be used to diagnose infertility due to decreased acrosin activity, as a screening method for identifying compounds with male sterility effects, and for identifying agents with developmental and/or genetic effects.