Characterization of the lectin binding pattern in human spermatozoa after swim-up selection

Capacitation is characterized by a hyperactivated pattern of sperm motility. The acquisition of highly motility is present in the early stages of capacitation. Sperm progressive motility is one of the most important parameters for determining the suitability of semen for processing. However, previous studies have shown that some sperm showing good motility have membrane damage. The aim of our study was to characterize the lectin staining pattern on the sperm plasma membrane of unselected and selected human sperm of normozoospermic donors. Sperm selection was performed by the swim-up technique. Fourteen samples from healthy consenting donors classified as normozoospermic according to the World Health Organization were used. We observed changes in the distribution of the carbohydrate residues after the swim-up selection. With Triticum vulgaris, the most abundant pattern was dotted labeling all over the head plasma membrane in the unselected sperm. However, this lectin was distributed homogenously over the acrosomal region after selection. With Arachis hypogaea, the most abundant pattern in fresh sperm was a highly stained acrosomal region. In the highly motility sperm population, the most frequent pattern was dotted fluorescence on the acrosomal region and a highly stained equatorial segment. Meanwhile, with the Aleuria aurantia and Canavalia ensiformis lectins, the most representative patterns were the same before and after the swim-up selection. Our data indicate that modifications which occur in carbohydrate residues during swim-up selection could be important for the regulation of progressive motility and prepare the sperm for capacitation.

This work was supported by Fundación Salud 2000 and the Research Pro-Vice-Chancellorship of the University of Alicante.