ANALYSIS OF THE EXTENT TO WHICH SPERM MOVEMENT CAN PREDICT THE RESULTS OF IONOPHORE-ENHANCED FUNCTIONAL ASSAYS OF THE ACROSOME REACTION AND SPERM-OOCYTE FUSION

This study has examined the extent to which the information generated by ionophore-enhanced bioassays of the acrosome reaction and sperm - oocyte fusion might be predicted from the computer-aided analysis of sperm motility. Strong correlations (r similar to 0.7) were observed between specific components of sperm movement in semen and the potential for A23187-induced sperm-oocyte fusion, generating a stepwise regression coefficient of R = 0.663 on the basis of two criteria, percentage progressive motility and amplitude of sperm lateral head displacement (ALH). The movement characteristics of the spermatozoa recovered from the Percoll gradients gave an even higher R value of 0.838 on the basis of four variables (percentage rapid, average path velocity, straightness and ALH). In contrast, the ability of human spermatozoa to undergo acrosome reaction in response to A23187 exhibited a limited correlation with sperm movement, whether these measurements were made in the original semen sample or following Percoll purification (R similar to 0.4). These results have diagnostic implications, since sperm-oocyte fusion and the acrosome reaction clearly differ in their relative dependence on sperm motility. In practical terms, it should be noted that the computer-aided analysis of sperm movement was shown to provide up to 70% of the information generated by the more laboured assessment of sperm-oocyte fusion.