EFFECT OF PLATELET-ACTIVATING-FACTOR ON MOTILITY AND ACROSOME REACTION OF HUMAN SPERMATOZOA

The effect of platelet-activating factor (PAF) on motility parameters and induction of the acrosome reaction in human spermatozoa was invest igated in 36 unselected men with different degrees of initial sperm mo tility. The characteristics of sperm movement were assessed by compute r-assisted sperm analysis (Hamilton-Thorn Motility Analyser) and the p ercentage of acrosome-reacted spermatozoa was evaluated after 1 h incu bation with PAF (10 nM) and staining with fluorescent peanut lectin. W e found that short-term (4 h max) incubation with PAF significantly en hanced total and progressive sperm motility as well as acrosome reacti on. An increase of sperm motility in response to PAF was present in 16 out of the 25 subjects studied (defined as responders) and was invers ely correlated with basal motility. In the 11 samples (six responders and five non-responders) where the incubation with PAF was prolonged o vernight, an increase of sperm motility was present in all the subject s studied. Similarly, an increase in numbers of acrosome reactions in response to 10 nM PAF was present in 20 out of the 26 subjects examine d, and was inhibited by the PAF receptor antagonist L659 989. Our resu lts indicate a possible physiological role for PAF in fertilization an d suggest a potential use of PAF in in-vitro fertilization techniques in cases of reduced sperm motility.