Pathophysiological interaction of dextran sodium sulfate-induced colitis and diet-induced hepatic lesions in mice

Nonalcoholic fatty liver disease (NAFLD) is a lifestyle-related disease. A gut-liver axis is involved in the progression of NAFLD. Disruption of the intestinal barrier function is an exacerbating factor of NAFLD. In this study, we have investigated the interaction between colitis and NAFLD in mouse models of dextran sodium sulfate (DSS)-induced colitis and diet-induced NAFLD-like lesions. Male C57BL/6J mice were provided with a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) and 1.25% DSS water for 3 weeks. The DSS water was administered intermittently. In the large intestine, the DSS-treated groups clearly demonstrated inflammation. Dilation of crypt and goblet cells was observed in the DSS + CDAHFD group. The expression of minor inflammation-related genes was increased in the CDAHFD group. In the liver, the CDAHFD group demonstrated non-alcoholic steatohepatitis (NASH)-like lesions. The number of C-X-C motif chemokine ligand 16 (CXCL16)-positive cells increased in the CDAHFD group and tended to increase in the DSS + CDAHFD group. Toll-like receptor 4 (TLR4)-positive cells were observed mainly in gallbladder epithelial cells in all groups and were more pronounced in the DSS-administered groups. Inflammation-related genes were upregulated in the DSS group. The expression of fibrosis-related genes increased in the DSS + CDAHFD group. DSS-induced colitis and CDAHFD-induced NASH interacted with each other. NAFLD lesions were induced by CDAHFD and exacerbated by TLR4 and CXCL16 in DSS-induced colitis. Colitis is induced by DSS and exacerbated by changes in the intestinal environment due to liver injury. This combined model was useful in analyzing early lesions of liver-gut axis for NAFLD.