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 cells with lecithin liposomes.

DESIGN

A randomized, blinded-controlled experiment.

SETTING

Andrology laboratory at the Lis Maternity Hospital.

PATIENT(S): Fifteen fertile sperm donors and 10 subfertile men.

INTERVENTION(S): Incubation of sperm samples with either control medium or 1 mg/mL of liposomal lecithin for 2 hours.

MAIN OUTCOME MEASURE(S): Expression of mannose-ligand receptors as evaluated by mannosylated bovine 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 86% +/- 4.8%, 11% +/- 3.4%, and 3% +/- 1.6%, respectively, after treatment with control medium and 71% +/- 5.7%, 22% +/- 3.5%, and 7% +/- 2.5%, respectively, after treatment with lecithin. The same effect of lecithin was observed in the 10 sperm samples from subfertile men. The mean +/- SE numbers of sperm that bound to hemizonae after treatment with control medium or lecithin were 116 +/- 32.4 and 176 +/- 29.6, respectively. 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 acrosoine-reacted patterns and enhances the binding capacity of the sperm cells.