EXPRESSION OF MANNOSE-LIGAND RECEPTORS ON HUMAN SPERMATOZOA - EFFECT OF LECITHIN AND ASSOCIATION WITH SPERM BINDING TO THE ZONA-PELLUCIDA

Objective: To evaluate the change in the expression of mannose-ligand receptors and sperm binding capacity after the incubation of sperm cel ls with lecithin liposomes. Design: A randomized, blinded-controlled e xperiment. Setting: Andrology laboratory at the Lis Maternity Hospital . Patient(s): Fifteen fertile sperm donors and 10 subfertile men. Inte rvention(s): Incubation of sperm samples with either control medium or 1 mg/mL of liposomal lecithin for 2 hours. Main Outcome Measure(s): E xpression of mannose-ligand receptors as evaluated by mannosylated bov ine serum albumin-fluorescein isothiocyanate and sperm binding to the zona pellucida as evaluated by the hemizona assay. Result(s): The mean +/- SE percentages of spermatozoa with patterns I, II, and III were 8 6% +/- 4.8%, 11% +/- 3.4%, and 3% +/- 1.6%, respectively, after treatm ent with control medium and 71% +/- 5.7%, 22% +/- 3.5%, and 7% +/- 2.5 %, respectively, after treatment with lecithin. The same effect of lec ithin was observed in the 10 sperm samples from subfertile men. The me an +/- SE numbers of sperm that bound to hemizonae after treatment wit h control medium or lecithin were 116 +/- 32.4 and 176 +/- 29.6, respe ctively. Statistically significant correlations were observed between the shift in patterns II and III and the enhancement of sperm binding after lecithin treatment (r = 0.44 and 0.6, respectively). Conclusion( s): Lecithin shifts the expression of mannose-ligand receptors to the capacitated and acrosome-reacted patterns and enhances the binding cap acity of the sperm cells. (Fertil Steril(R) 1998;70:766-70. (C) 1998 b y American Society for Reproductive Medicine.).