THE EFFECT OF SEMINAL PLASMA ON HUMAN SPERM-ZONA PELLUCIDA BINDING

The aim of this study was to determine the effect of different concent rations of seminal plasma (SP) in insemination medium on human sperm-z ona pellucida (ZP) binding. The effects of fresh SP [50% (n = 10) and 1% (n = 9)], frozen-thawed versus fresh SP [5% (n = 10)] and frozen-th awed SP [5% (n = 10) and 1% (n = 9)] on sperm-ZP binding were examined using hemizona assays. The validity of the hemizona assay as performe d in this study was also examined. Relative sperm binding percentages were determined for respective hemizonae, and the hemizona index was c alculated for each experimental group and compared statistically. The 50% native SP inhibited sperm-ZP binding by similar to 70% (P = 0.0051 ), while 1% native SP enhanced sperm-ZP binding by similar to 350% (P = 0.0051). Significantly more spermatozoa (mean +/- SD, 172.00 +/- 54. 12) bound to zonae in the presence of 5% frozen-thawed SP than with 5% SP that had not been frozen (mean +/- SD, 127.00 +/- 69.18; P = 0.043 1). The 1 and 5% frozen-thawed SP stimulated sperm-ZP binding by simil ar to 400 and similar to 250% respectively (P = 0.0077 and 0.0051 resp ectively). It is concluded that SP concentrations found in inseminatio n media during assisted reproductive techniques do not Inhibit but in fact enhance sperm-ZP binding.