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

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

Buenos Aires

Simposio; 3rd Argentinian Symposium on Glycobiology 2019.; 2019

Universidad Nacional de San Martin

Immature spermatozoa undergo several molecular changes on their surface during epididymal maturation, including addition, removal, and/or modification of external sugars on glycolipids or glycoproteins. These events are a direct result of exposure to, and interaction with, epididymal luminal environment. In this study we evaluated the N-acetyl-glucosamine (NAG) content of the plasma membrane glycoproteins in bull spermatozoa during their epididymal maturation. Fresh epididymides from bulls (Aberdeen Angus) 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 FITC- or biotinconjugated lectins (WGA and BS-I, respectively). By FACS we observed that NAG signal increases progressively from caput to ejaculated sperm. In addition, after blotting sperm glycoproteins onto nitrocellulose membranes, and detection with biotynilated lectin we observed a decrease in the NAG content of some glycoproteins, whereas the signal increases in a ∼60 kDa protein of cauda spermatoza. No major changes were observed in the GAL content between sperm samples. We also observed that NAG activity increases from caput to cauda along with a redistribution of the enzyme to the epididymal fluid. These changes could provide new insights about carbohydrate rearrangement that can be used as parameters for sperm maturation.