Changes in N-acetylglucosamine of bull spermatozoa associated to epididymal maturation

ALVAREZ P; CARVELLI L; AGUILERA AC; SOSA MIGUEL ANGEL

San Luis

Congreso; XXXV Reunión Anual de la Sociedad de Biología de Cuyo; 2019

Sociedad de Biología de Cuyo

Spermatozoa undergo several molecular changes on their surface during epididymal maturation including addition, removal, and/or modification of external sugars and glycoproteins. In this study, we evaluate the changes that occur in N-acetyl-glucosamine (NAG) residues of the plasma membrane glycoproteins of bull spermatozoa during their epididymal maturation. Fresh epididymides from bulls (Aberdeen Angus) were dissected into caput, corpus and cauda and the sperms were obtained by slicing of the tissue and centrifugation. Ejaculated spermatozoa were obtained from cryopreserved samples. We evaluated the content of NAG and galactose (GAL) in sperm glycoproteins by using FITC or biotin conjugated lectins (WGA for NAG and BS-I for GAL). By FACS we observed that a population of sperm increase progressively the NAG content whereas other population disappear from caput to eyaculated sperm. After blotting the sperm glycoproteins in nitrocellulose membranes, we observed a diminution in the NAG content of several glycoproteins, except a 60 kDa protein, which appear to increase NAG residues in cauda. However, we did not observed changes in the content of GAL. We also evaluated the activity of N-acetil-glucosaminidase (NAG) in the epididymal fluid. It was observed that NAG activity increased from caput to cauda along with a redistribution of the enzyme to the epididymal fluid. These changes could provide new insights into molecular rearrangement that can be used as parameters for sperm maturation.