"Llama sperm binding to oviductal epithelium involves N-acetyl galactosamine recognition¡±

APICHELA, SA; JIMÉNEZ DÍAZ, MA; VALSZ GIANINET, JN; ROLDÁN OLARTE, EM; MICELI, DC

Budapest, Hungria

Congreso; 16th International Congress on Animal Reproduction; 2008

INTRODUCCION: Sperm binding to oviductal epithelium would be involved in the sperm reservoirs formation. In other animals, a species-specific carbohydrate recognition take part in the sperm-oviduct interaction but in llama it remains unknown. Knowing the type of carbohydrate residues that could participate in the sperm adhesion to the llama oviductal epithelium was one of the objetives of this study. MATERIAL AND METHODS: The distribution of glycoconjugates in llama oviducts was examined by lectin-histochemistry. Uterotubal Junction (UTJ), Isthmus and Ampulla where labelled with WGA, WGAs, UEA-1, DBA, RCA 120, Con A, PSA, LCA, PHA E, PHA L, GSL, and SJA lectins-FITC/rhodamine conjugated and observed by Confocal Laser Scanning Microscopy. Competition binding assays with carbohydrates and lectins were used for assessing the sperm binding to oviductal epithelium in vitro. Epithelial cell explants (CEC) were obtained from UTJ oviductal epithelium of non mated females. CECs were incubated with 10 ug/ml of DBA, WGA, UEA1 or PNA for 20 min  (39¨¬C, 5% CO2) and then aliquots of washed fresh motile sperm (obtained by artificial vagina) were added. In parallel, fresh sperm were incubated with 10 ug/ml of glucose, manose, galactose, or N-acetyl galactosamine and then co-incubated with CECs. After one hour, the explants were fixed, stained, rinsed, and the sperm binding index (BI=sperm number/0.1 mm2) was calculated. RESULTS AND DISCUSSION: No differences where found between oviductal segments regardind the carbohydrate residues distribution on the apical cell surface. Abundant ¥á-mannopyranosyl, ¥á-glucopyranosil, N-acetyl glucosamine and N-acetyl-neuraminic acid residues and scarce ¥á-linked N-acetyl-galactosamine and ¥â-galactosyl residues were detected. Neither ¥á-L- N- acety- galactosamine fucopyranosyl nor ¥â-N-acetyl-galactosamine residues were were distinguished. N-Acetyl glucosamine, and galactose were the main carbohydrate that inhibited sperm-CECs binding, as well as DBA lectin. Taken into account these results, the binding sites for N-acetyl galactosamine on sperm were corroborate by using N-acetyl galactosamine-PAA-FITC conjugate. In agreement, sperm were strongly labelled suggesting thet N-Acetyl galactosamine could be implicated in a specific interaction between llama sperm and UTJ oviductal epithelium.