Immunohistochemical Study of Galectin-3 in the Bull Testis and Epididymis

Abstract

The expression of galectin-3, a member of the β-galactoside-binding protein family, was examined in the testis and epdidymis of sexually mature and immature bulls. Western blot analysis showed varying levels of galectin-3 expression in the testis and epididymis. Galectin-3 immunoreactivity was higher in the maturetestis and epididymis than in the immature organs. Galectin-3 expression was immunolocalized primarily in interstitial cells in the immature bull testis and in the peritubular myoid cells andinterstitial cells in the mature testis. In the immature epididymis head, galectin-3 was detected in the epithelium and basal cells, but not in the stereocilia and connective tissue. Moderate levels of galectin-3 were detected in the sperm of the mature epididymis head, but low levels were found in the stereocilia, epithelium, and connective tissue. Moderate levels of the protein were detected in the epithelial cells of the immature epididymis body, while lower levels were found in the basal cells, and no staining was detected in the connective tissue. The mature epididymis body showed moderate levels of galectin-3 immunostaining in the stereocilia and epithelium, low levels in the connective tissue, and no staining in the basal cells and sperm. The only galectin-3 staining found in the immature epididymis tail was low levels in the epithelium. In contrast, the mature epididymis tail showed high levels of galectin-3 in the epithelium, moderate levels in the basal cells, and low levels in connective tissue. No staining was found in the stereocilia or sperm. These findings suggest that galectin-3 expression plays a role in the maturation and activation of sperm in bulls.