DEVELOPMENT OF IMMUNOREACTIVITY TOWARDS EPITHELIAL CADHERIN DURING EPIDIDYMAL SPERM MATURATION. STUDIES IN BOVINE AND MURINE MODELS.

CABALLERO J; VEIGA M F; FORNES M W; SULLIVAN R; VAZQUEZ M H

Buenos Aires

Congreso; Reunón Anual Soc. Argentina de Biol.; 2006

Sociedad Argentina de Biología

DEVELOPMENT OF IMMUNOREACTIVITY TOWARDS EPITHELIAL CADHERIN DURING EPIDIDYMAL SPERM MATURATION. STUDIES IN BOVINE AND MURINE MODELS. Caballero J.1*, Veiga M.F.1*, Fornés M.3, Sullivan R.4, Vazquez-Levin M.H.1 1Inst. Biología y Medicina Exp. (IBYME, CONICET-UBA) 3IHEM, CONICET, 4Universidad Laval, Canadá. caballero@dna.uba.ar & veiga@dna.uba.ar. *Equally contributed to the work. Sperm acquire fertilizing ability during epididymal maturation. Epithelial cadherin (Ecad) is a Ca+2 dependent cell-cell adhesion molecule present in cauda epididymal mouse and ejaculated bull spermatozoa, in cell regions proposed to participate in fertilization (1,2). The aim of the study was to assess Ecad localization in epididymal spermatozoa recovered from caput, corpus and cauda epididymis, and compare it with that on testicular sperm cells. In addition, expression of Ecad in mouse and bovine epididymis was confirmed by immunohystochemistry, and immunodetection in epididymosomes was evaluated by immunoelectron microscopy (IEM) and Western immunoblotting (WIB). Evaluations were done using specific anti Ecad antibodies towards different protein regions. Immunocytochemical studies revealed a specific signal for Ecad in the apical ridge (bull), acrosome (bull,mouse), and the post-acrosomal region (bull,mouse) of caput, corpus and cauda sperm; contrasting, negligible levels of Ecad were detected in cells recovered from the testis, showing a homogeneous localization along the cell (mouse) or only in the postacrosomal region (bovine). Expression of Ecad in the epididymis was confirmed in both species, and its presence in epididymosomes was revealed by IEM (mouse) and by WIB (bovine), showing Ecad forms of 120, 110, and 35 KDa. In conclusion, remarkable differences in Ecad immunodetection were found between testicular and epididymal sperm. Its expression in the epididymis and presence in epididymosomes suggests a role of these vesicles in Ecad transfer during epididymal maturation. (1) Veiga et al. J Androl (2005), Suppl. March April, pg. 83. (2)Caballero et al. J Androl (2006), Suppl.March April, pg. 72. Trabajo inédito