N-ACETYLGLUCOSAMINE CONTENT CHANGES IN BULL SPERM DURING EPIDIDYMAL MATURATION

AGUILERA CAROLINA; LEIVA NATALIA; ALVAREZ PABLO; DIANA ALESIA; SOSA MIGUEL

San Luis

Congreso; XXXVII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2019

Sociedad de Biología de Cuyo

After leaving the testis, spermatozoa undergo several molecular changes up to reach the female genital tract. Most of these modifications occur during epididymal transit as a direct result of exposure to, and interaction with, epididymal luminal environment. Among these modifications, addition, removal and/or modification of external sugars on glycolipids or glycoproteins have been described in different species. The aim of this study was to evaluate changes in N-acetyl-glucosamine (NAG) content of the plasma membrane glycoproteins in bull spermatozoa during their epididymal maturation. For this purpose, fresh epididymides from bulls (Aberdeen Angus) were used. Organs were dissected into caput, corpus and cauda and the sperm were obtained by slicing of the tissue and centrifugation. Ejaculated spermatozoa were obtained from cryopreserved samples. NAG and galactose (GAL) were evaluated in sperm glycoproteins by using respectively WGA and BS-I lectins conjugated with either FITC-for flow cytometry or with biotin for blotting assay. By flow cytometry we observed that NAG detection increased progressively from caput to ejaculated sperm. By blotting sperm glycoproteins onto nitrocellulose membranes, and subsequent detection with biotynilated lectins we observed a decrease in the NAG content of some glycoproteins, while the signal increased in a 60 kDa protein of cauda spermatoza. No major changes were observed in the GAL content between sperm from caput to cauda. We also observed that β-N-acetyl-glucosaminidase activity increased from caput to cauda and the enzyme is redistributed to the epididymal fluid. These changes could provide new insights about carbohydrate rearrangement that can be used as parameters for sperm maturation.