Association of seminal plasma motility inhibitors/semenogelins with sperm in asthenozoospermia-infertile men.

Seminal plasma motility inhibitors (SPMIs) are proteinase-resistant fragments of semenogelin I and II (Sgs), which are the major proteins of semen coagulum. SPMIs inhibit the motility of spermatozoa, and Sgs are thought to be natural regulators of human sperm function. The mechanism underlying sperm motility regulation and its association with defective motility in infertile men remain unclear. The purpose of this study was to investigate the association between SPMIs and spermatozoa in infertile men with asthenozoospermia. Fifty-four semen samples from 37 asthenozoospermic patients and 17 samples from 9 normal healthy subjects were analyzed. Spermatozoa, washed by Percoll density gradients, were immunostained with anti-SPMI antibody and subjected to flow cytometric analysis. The proportion of spermatozoa labeled with the antibody and the average intensity of fluorescence labeling per spermatozoa were analyzed in relation to the parameters used for semen analysis. A significant negative correlation was found between sperm motility and the proportion (R = -0.68) and intensity (R = -0.38) of labeling. These results suggest that SPMIs remain on the sperm surface after liquefaction. This might account for some disorders of sperm motility observed in infertile men with asthenozoospermia.