The objective was to examine the expression and distribution of tight junction (TJ) and adherens junction (AJ) proteins in canine duodenal and colonic mucosa. Biopsy specimens of the duodenum and colon were obtained via endoscopy from four healthy Beagles. The expression patterns and subcelluar localization of claudin-1, -2, -3, -4, -5, -7 and -8; E-cadherin; and β-catenin in the duodenum and colon were analyzed.

In the duodenum, there was clear expression of claudin-3 and -5, E-cadherin and β-catenin proteins and weak expression of claudin-7 protein. In contrast, there was clear expression of claudin-2 and -3, E-cadherin and β-catenin proteins and weak expression of claudin-5 and -7 proteins in the colon, as determined by use of immunoblotting. As determined by immunofluorescence microscopy, the duodenum and colon had staining for claudin-3 and -5, E-cadherin and β-catenin in the most apical region and staining for claudin-7 in the basolateral region. Staining for claudin-2 was also observed in the colon.

These results may provide valuable information for evaluating the importance of these TJ and AJ proteins in the pathogenesis of inflammatory bowel disease in dogs.

Source : H. Ohta et al., 2011. Expression and subcellular localization of apical junction proteins in canine duodenal and colonic mucosa. AJVR 72: 1046-1051. doi: 10.2460/ajvr.72.8.1046