HEXOSAMINIDASE FROM CAUDA EPIDIDYMAL FLUID COULD PARTICIPATE IN REMODELING CARBOHYDRATE ON THE SURFACE OF BULL SPERMATOZOA

ALVAREZ P; BUTAZZONI A; SOSA MA; ROBINA I; AGUILERA AC

Congreso; XXXIX Reunión Anual de la Sociedad de Biología de Cuyo; 2021

Sociedad de Biología de Cuyo

Spermatozoa undergo biochemical and morphological changes during the epididymal transit, resulting in the gametematuration. Among the several proteins secreted by the epididymal epithelium, hexosaminidase (HEX) is the most abundantglycosidase in bull epididymal fluid and it represents upon 3% of the total secretion in the distal part of the organ. Given thatHEX is a lysosomal enzyme, it is still controversial whether this enzyme is active at the pH of the epididymal lumen andwhether it participates in the epididymal maturation. The aim of this study was to correlate the activity of HEX with thosechanges in N-acetyl-glucosamine (NAG) content observed in bull spermatozoa during epididymal maturation. By flowcytometry and fluorescence microscopy (using WGA FITC), we observed that NAG content on the sperm surface variesduring epididymal maturation. Interestingly, increased activity of HEX (measured by spectrofluorometry) at the epididymalpH (6.8) was detected in the cauda lumen. In order to determine if the epididymal HEX is responsible for NAG removal fromthe sperm surface, we performed an assay by incubating cauda fluid with spermatozoa obtained from the caput. We observedby flow cytometry that incubation with the fluid induced a significant decrease of NAG on the sperm surface, which waspartially reversed with synthetic inhibitors specific for HEX. Our results provide direct evidence that HEX from epididymalfluid may participates in removing NAG from spermatozoa, as a step of sperm maturation in bull epididymis.