Differential lectin binding patterns in the oviductal ampulla of the horse during oestrus.

The research investigates the patterns and sequence of glycoconjugates, chiefly sialoglycoconjugates, found in the oviductal ampulla (portion of the Fallopian tube) during oestrus (reproductive phase) in horses. The study indicates differences in these patterns between the ciliated and non-ciliated cells within this region and intimates possible functional implications of these variations.

Research Methodology

• The research revolved around the analysis of the oligosaccharide sequence of glycoconjugates, specifically sialoglycoconjugates, present in the horse oviductal ampulla during oestrus.
• The studying methods included the use of lectins, proteins that bind certain sugars, and pre-lectin techniques such as the KOH-neuraminidase procedure, used to remove sialic acid residues. Another utilized method was incubation with N-glycosidase F, used to cleave N-linked glycans.

Findings and Observations

• The ciliated cells revealed the presence of N-linked oligosaccharides throughout the cytoplasm.
• The cilia glycocalyx (a glycoprotein-rich layer covering cells) expressed both N- and O-linked (mucin-type) oligosaccharides. Both types showed a high variety of terminal sequences.
• In the non-ciliated cells, the entire cytoplasm contained N-linked oligosaccharides featuring terminal alphaGal and mucin-type glycans terminating with Forssman pentasaccharides.
• A few scattered non-ciliated cells displayed sialylated N-linked oligosaccharides featuring terminal Neu5Ac-GalNAc and O-linked glycans ending with a mix of neutral and/or alphaGalNAc, Neu5Ac alpha2,6Gal/GalNAc, Neu5AcGal beta1,3GalNAc.
• The supra-nuclear granules of non-ciliated cells mainly exhibited O-linked glycans rich in sialic acid residues.
• The luminal surface of non-ciliated cells showed N-linked oligosaccharides as well as mucin-type oligosaccharides. These molecules terminated with an array of neutral saccharides or sialylated sequences.
• Apical protrusions in non-ciliated cells scattered along the epithelium contained O-linked oligosaccharides with specific terminal components.

Conclusion of the Study

• The results revealed the presence of sialoglycoconjugates within the epithelium of the mare’s oviductal ampulla.
• The study confirmed the existence of varied lectin binding profiles between ciliated cells (those with hair-like structures helping in movement) and non-ciliated (secretory) cells.
• The discoveries also highlighted the existence of sub-types of non-ciliated cells, which could have functional differences along the ampullary epithelium of mare oviduct. In simpler terms, it signals that different types of cells in the same region can have different roles during the reproductive cycle.