Histology and Histochemical Distribution of Goblet Cells in the Descending Colonic Epithelium of the Swamp Buffalo (Bubalus bubalis)

Abstract

                Predominant glycoconjugates in the descending colon are synthesized and secreted by goblet cells. Changes in the chemical composition of the intestinal mucous affect the functioning of the large intestine. The expression of glycoconjugates in the colonic epithelium of buffaloes was studied using histochemical methods. Paraffin sections 3 μm thick were stained with the following reagents: 1) haematoxylin and eosin (H&E), 2) alcian blue (AB) pH 2.5, 3) periodic acid –Schiff (PAS), 4) AB pH 2.5 – PAS, 5) high iron diamine (HID), 6) HID–AB pH 2.5, and three lectins, 7) Arachis hypogeae (PNA), 8) Ulex europaeus (UEA-I) and 9) Triticum vulgaris (WGA). Neuraminidase was used before staining with PNA.

                The histology of the descending colonic epithelium is characterized by an absence of villi; the epithelium have numerous simple columnar crypts. The crypts consist of columnar absorptive cells and goblet cells. The goblet cells in the descending colon of buffaloes contained acid and neutral glycoconjugates, whose expression was increased from the lower crypts to the upper crypts. There were more sulphated glycoconjugates in the goblet cells of lower crypts than in upper crypts. The crypts of the upper areas showed more intense expression of carboxylated glycoconjugates and sialic acid together with D- galactose and N- acetylglucosamine. The expression of α -L- fucose was found in the goblet cells throughout all crypts. The results indicated that sulfomucin and α -L- fucose played a lubricating role, while sialic acid and sialoderivatives provided protection against pathogenic infection.