Lectin Histochemical Detection of Special Sugars on the Mucosal Surfaces of the Rat Alimentary Tract

Abstract

ABSTRACT. Surfaces of the most luminal positions of mucosae are fundamental settlement sites of indigenous bacteria throughout the rat alimentary tract. In these positions, also epithelial cell-shedding sites, the special sugar expression in the glycocalyx is very important as it provides possible ligands of bacterial lectins for attachment to epithelial cells. Therefore, the sugar expression in glycocalyx of epithelial cells was lectin-histochemically surveyed using 21 lectins throughout the rat alimentary tract. From the tongue to the nonglandular part of the stomach, -D-Man, -D-Glc and -D-GalNAc were detected on the surface of the keratinized stratified squamous epithelium. In the glandular part of the stomach,(1-4)GlcNAc and bisected triantennary N-glycans were detected on the surface of gastric superficial epithelial cells. From the duodenum to the ileum, (GlcNAc) 2-4 was expressed exclusively on the epithelial cells in the apical portions of the intestinal villi. From the cecum to the rectum,GalNAc) n and NeuNAc were expressed on the intestinal superficial epithelial cells. These results suggest that special sugars are expressed on the most luminal portions of mucosae as exclusive epithelial cell-shedding sites, and that sugar expression differs among the various segments of the alimentary tract. These site differences might reflect differences in resident bacterial species in the rat alimentary tract.KEY WORDS: alimentary tract, indigenous bacteria, lectin histochemistry, rat, sugar expression.

Immunohistochemical Study on the Secretory Host Defense System of Bactericidal Peptides in Rat Digestive Organs

“…On the other hand, the settlement of bacteria is generally achieved by the interaction of bacterial receptors, such as bacterial lectins, and their ligands, such as epithelial sugars. The sugars expressed on the epithelial cells differ greatly between the upper alimentary tract and other alimentary portions [39]. From these findings, the characterization of indigenous bacteria settlement might be decided by single or multiple effects of various factors, such as the site differences of bactericidal peptide secretion and epithelial sugars and the specificities of bactericidal proteins.…”

“…The fundamental colonization sites of indigenous bacteria have been determined to be the most luminal sites of the mucosae throughout the alimentary tract [38]. Several possible sugars specific for indigenous bacterial lectins are expressed strictly on late-apoptotic epithelial cells of the most luminal sites in rat jejuno-ileum [5] and whole alimentary tract [39]. The most luminal sites of both the intestinal villi and the domes of mucosal lymphatic follicles are also shedding sites of effete epithelial cells at the late apoptotic stage [27,28].…”

Immunohistochemical Detection of Toll-Like Receptor-2, -4 and -9 in Exocrine Glands Associated with Rat Alimentary Tract

“…Bacterial colonization in the gastrointestinal tract initiates immediately after birth, and the composition and number of indigenous bacteria are almost stable under physiological conditions in adults [6]. The fundamental settlement sites of indigenous bacteria are the surfaces of the most luminal portions of mucosa throughout the rat alimentary tract [10,19,20,38,39]. Indigenous bacteria proliferate from the apical portions of the intestinal villi into the intervillous spaces in the rat small intestine [38].…”

Immunohistochemical and Histoplanimetrical Study on the Spatial Relationship between the Settlement of Indigenous Bacteria and the Secretion of Bactericidal Peptides in Rat Alimentary Tract

“…Several possible sugars that are specific for indigenous bacterial lectins, are expressed restrictedly on the lateapoptotic epithelial cells of the most luminal sites of mucosa in the rat jejuno-ileum [3] and through the rat alimentary tract [28]. In the small intestine, the apices of both the intestinal villi and the domes of mucosal lymphatic follicles are unstable sites where apoptotic epithelial cells are incessantly shed into the intestinal lumen [18,19].…”