Effects of sperm preincubation in rabbit uterus and of imidazole on the penetration of zona-free hamster eggs by bull and boar spermatozoa in vitro.

Abstract

In vitro penetration of zona-free hamster eggs by bull and boar sperma-tozoa was investigated. The ejaculated spermatozoa were washed and preincubated for specified hours in the uteri isolated from mature does or for 4. 5 h in the incubation medium (BWW medium) with or without addition of 10 mM imidazole and then incubated with the eggs for 7 h. It was found that the penetration can be effected by spermatozoa of both species after their uterine preincubation but not after preincubation in the media only. The beneficial effect of imidazole was alsoobserved on the penetration by bull spermatozoa after their uterine preincubation but not on the penetration by boar sperm-atozoa. Three and five hours of uterine preincubation were required for obtaining high proportions of eggs penetrated by boar and bull spermatozoa, respectively. It is suggested that bull and boarspermatozoa were capacitated in isolated rabbit uteri and imidazole may facilitate the induction of acrosome reaction of capacitated bull spermatozoa.