CHANGES IN THE MEMBRANE OF BULL SPERMATOZOA DURING EPIDIDYMAL MATURATION

AGUILERA AC, ; CARVELLI L,; BANNOUD N,; SOSA MA

San Juan

Congreso; SECOND JOINT MEETING OF THE BIOLOGY SOCIETIES FROM ARGENTINA; 2011

The epididymis is involved in sperm maturation through the secretion of factors into the lumen; some of them are glycan-modifiying enzymes that catalyse molecular changes in sperm membrane. We intend to study the molecular changes that occur in 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. We measured the activity of the glycosidases, beta-N-acetil-glucosaminidase (NAG), alpha-mannosidase (MAN), beta-galactosidase (GAL) and beta-glucosidase (GLU) associated to the gametes. We also evaluated the content of fucose in sperm glycoproteins by using a FITC-conjugated lectin UEA-I (for Flow cytometry and microscopy) or biotin-conjugated UEA-I (for Western Blot). It was observed that NAG activity increased in spermtozoa from caput to cauda, whereas MAN was decreased along the epididymal transit. We also observed that content of fucose on spermatozoa glycoproteins decreased during their epididymal maturation, except a ∼50 kDa protein, which is fucosylated in cauda. By fluorescence microscopy, we observed a redistribution of fucose from a strong post-acrosomal to a weak diffuse staining. These changes could provide new insights into molecular rearrangement that can be used as parameters for sperm maturation.