A new combined in-vitro test model for the identification of substances affecting essential sperm functions [published erratum appears in Hum Reprod 1997 Nov;12(11):2580]

Binding of mammalian spermatozoa to the zona pellucida and the induction ofthe acrosome reaction are prerequisites for successful oocytefertilization. It has been postulated that xenobiotics that are released inthe environment as well as exposure to pharmaceutical medications may beassociated with reproductive problems in men and wildlife. Examiningphysiological and non-physiological effects of particular compounds onsperm functions requires high quality in-vitro test systems. We establisheda reliable combined in-vitro test system with bovine gametes and evaluatedif aliquots of pooled post-thaw spermatozoa are suitable for examiningessential sperm functions. Using cryopreserved semen, the PSA-FITC/Hoechst33258 staining procedure was applicable to evaluate the acrosomal statusand cell viability. In the bovine hemizona assay, hemizona indices revealedno differences between cryopreserved and fresh semen. Treatment ofpost-thaw bovine spermatozoa with progesterone (1 microM or bovinefollicular fluid (20%) induced the acrosome reaction from 12% (untreatedspermatozoa) to 25% (P < 0.001) and to 22% [corrected] (P < 0.01),respectively. Incubation of both compounds (1 microM progesterone and 20%follicular fluid) raised the percentage of acrosome-reacted spermatozoa to30% (P < 0001). Our results demonstrate that cryopreserved semen can beintegrated into an in-vitro screening model for reproductive toxicologytesting. Pooled, cryopreserved bovine spermatozoa will thus permitreproducible experiments for clinical and basic science purposes and mayalso be applicable for the human system.