Distribution of sialoglycoconjugates in the epithelium of the dromedary oviduct

The glycoproteins constitute a macromolecular component required for the normal functions of the oviduct. Among the glycoconjugates, sialoderivates are considered the most important glycans for the cell-to cell interaction occurring in the oviduct. The aim of this study was to investigate the distribution of sialoglycoconjugates in the oviduct epithelium of dromedary by means of lectin histochemistry. Oviducts from two dromedaries were fixed in 4% (w/v) neutral formalin and embedded in paraffin wax. Sections were stained with MAL II, SNA, PNA, DBA before or after sialidase treatment. The luminal surface of entire oviduct reacted with all the used lectins. DBA and PNA reactivity increased in infundibulum and isthmus, respectively, after sialidase treatment. These results suggest regional differences of the glycoconjugates expressed in the dromedary oviduct. Infundibulum and isthmus luminal surface were characterized by sialoderivates terminating with NeuAcForssman pentasaccharide and NeuAcGalβ1,3GalNAc, respectively. The entire the luminal surface of oviduct contained sialoglycoconjugates ending with Neu5acα2,3Galβ1,4GlcNAc, Neu5Acα2,6Gal/GalNAc, as well as asialoglycoproteins terminating with Galβ1,3GalNAc and Forssman pentasaccharide. It is possible to infer that, as in other mammals, the sialoglycoconjugates of the dromedary oviduct could have some role in the adhesion of sperm to epithelium, in sperm capacitation as well as in sperm-egg interaction and in early embryo development