Role of carbohydrates in the attachment of equine spermatozoa to uterine tubal (oviductal) epithelial cells in vitro
Dobrinski, I.; Ignotz, G.G.; Thomas, P.G.; Ball, B.A.
American Journal of Veterinary Research 57(11): 1635-1639
ISSN/ISBN: 0002-9645 PMID: 8915444 Accession: 002948739
In experiment 1a, fluorescent-labelled spermatozoa were cocultured with monolayers of oviductal epithelial cells (OEC) in the presence of 50 mM glucose, fructose, galactose, mannose, N-acetyl glucosamine, N-acetyl galactosamine, or N-acetyl neuraminic acid, or 10 mg of fetuin or asialofetuin/ml in modified Tyrode's solution (TALP), or in TALP alone. After 2 h of coculture, numbers of attached spermatozoa were counted by fluorescence microscopy and analysis of digitized images. In experiment 1b, progressive motility, viability, acrosomal integrity and capacitation status were determined in spermatozoa incubated for 2 h in the presence of the respective monosaccharides and glycoproteins or in TALP alone. In experiment 2, proteins isolated from the peri-acrosomal plasma membrane of equine spermatozoa were subjected to galactose affinity chromatography and subsequent one-dimensional SDS-PAGE and silver staining. Numbers of spermatozoa attached to OEC were reduced after all treatments except N-acetyl glucosamine, compared with incubation in TALP alone. The lowest numbers of spermatozoa were bound in cultures incubated in the presence of galactose and asialofetuin. Spermatozoal motility was lower after incubation for 2 h in the presence of fetuin, compared with control, and incubation in the presence of fetuin or asialofetuin caused a significant increase in the percentage of capacitated spermatozoa, compared with control. Affinity chromatography of peri-acrosomal plasma membrane proteins revealed a galactose-binding protein of about 66 kDa. It is suggested that recognition of glycoconjugates with exposed galactosyl residues on OEC by galactose-binding proteins on the peri-acrosomal plasma membrane of equine spermatozoa could mediate the attachment of equine spermatozoa to OEC in vitro.