Glycosylation in Canine Placentas

Abstract

This article describes the carbohydrate composition of early and mature placentas from bitches, detected by lectin histochemistry. Formalin-fixed placental samples from 11 mixed-breed bitches have been assigned to the 'early' or the 'mature' placenta group, processed by the routine histological technique and labelled with a panel of 14 biotinylated lectins. The glycan distribution was almost completely preserved over pregnancy. Cytotrophoblast cells expressed high-mannose N-linked residues and N-acetyl-D-glucosamine, whereas mannose N-linked residues, N-acetyl-D-glucosamine and β- and α-D-galactose/N-acetyl-D-galactosamine have been found in the syncytiotrophoblast. The maternal and foetal endothelial binding pattern was enriched in β-D-galactose, α-D-mannose in non-bisected bi/tri-antennary N-linked complex and Galα1,3Gal-Galα1,4Gal. Both deep and superficial glands showed a great variety of glycoconjugates, such as D-mannose, D-glucose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, galactose, N-acetylneuraminic acid and fucose. Most results in this study were consistent with those previously reported in canine and feline mature placentas; here, early placentas have been analysed and the lectin binding pattern of mature placentas has been further described. These studies on canine placentas contribute to detecting and understanding glycome changes in pathophysiological conditions.

Keywords: bitches; dogs; endotheliochorial placenta; glycoconjugates; lectin histochemistry; trophoblast.