Distribution of N- and O-linked oligosaccharides on surface of spermatozoa from normal and infertile subjects

Sperm glycocalyx modifications are very important for gamete recognition and fertilisation in mammals. These processes may be associated with specific changes in the content and distribution of surface carbohydrates. The purpose of this study was to determine the distribution of surface carbohydrates in human spermatozoa from normal and oligospermic subjects. Fifteen ejaculates each from normal fertile and oligospermic individuals were analysed. N-linked and O-linked surface carbohydrates were detected by fluorescence microscopy using fluorescein isothiocynate-conjugated lectins. Triticum vulgaris agglutinin (WGA)-binding sites were found to be decreased on acrosomal domain in spermatozoa from oligospermic individuals, while no changes were observed in the binding sites of Concanavalin ensiformis, Peanut agglutinin and Lens clunaris agglutinin. A reduction in binding sites for soyabean agglutinin and Ricinus communis agglutinin was observed on the acrosomal domains in spermatozoa from oligospermic individuals. Changes in sperm glycocalyx observed in this study provide new insights into molecular rearrangement of sperm membrane in infertility.