Sperm select penetration test reveals differences in sperm quality in strains with different Y chromosome genotype in mice.

Mouse sperm penetration into a hyaluronic acid polymer (Sperm Select), hypoosmotic swelling in distilled water (water test), and eosin-Y staining were studied in sperm samples from males belonging to five inbred strains of mice (CBA, KE, KE-YCBA, B10.BR, and B10.BR-Ydel), which differ in the proportion of abnormal sperm heads and in efficiency of fertilization. Correlation coefficients, calculated from mean values for each strain, showed that Sperm Select penetration (to the depth of 1-2 cm) was significantly correlated with both sperm motility and fertilization efficiency, while correlation with the proportion of normal spermatozoa did not reach the level of significance. The indices of the water test and erosin Y staining were correlated with each other but not with Sperm Select penetration. In comparison with the B10.BR strain, its mutant strain B10.BR-Ydel, with a large deletion in the long arm of the Y chromosome and characterized by highly elevated proportion of abnormal sperm and low fertilization efficiency, showed lower values of the indices of all tests, suggesting that the partial deletion of the Y chromosome has affected various aspects of sperm morphology and function. On the other hand, for two consomic strains (KE and KE-YCBA with the Y chromosome introduced from the CBA strain), the difference in sperm morphology and fertilization rate was correlated with Sperm Select penetration but not with hypoosmotic swelling or eosin-Y staining; this suggests that only some aspects of sperm physiology are due to genetic differences between YKE and YCBA chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS)