The selection of Y-chromatin positive spermatozoa and subsequent in vitro penetration through cervical mucus.

We carried out a check of Ericsson's data on the possibility of separating out Y-spermatozoa and their selective enrichement. Layers of spermatozoa were laid on BSA media of various concentrations, filtered and the Y-chromatin proportion was determined. The method used was that of fluorochromation with quinacrine mustard. Our selection experiments revealed a lower enrichment effect of Y-chromatin positive spermatozoa than that recorded by Ericsson et al. An average enrichment of 75% was obtained. Modifications carried out with other variants of the BSA gradient overlays achieved varying enrichment effects respectively. In order to check the subsequent progressive motility of the spermatozoa selected, we performed tests on in vitro penetration through cervical mucus, using the previously enriched Y-spermatozoa material. After the in vitro penetration test we were able to investigate the Y-chromatin proportion of a sufficient number of highly mobile spermatozoa after 60-mm penetration per hour. There was no significant change in the enrichment effect of the Y-spermatozoa during the in vitro penetration test.