Xia-Yu-Xue Decoction Inhibits Intestinal Epithelial Cell Apoptosis in CCl4-Induced Liver Fibrosis
Background/Aims: Intestine-derived endotoxin is thought to play a role in the development of liver fibrosis. However, the pathological change in the intestine during liver fibrosis is still poorly understood. Here, we investigated the effects of Xia-yu-xue decoction (XYXD) on intestinal inflammation, apoptosis, and tight junction integrity in the carbon tetrachloride (CCl4)-induced liver fibrosis. Methods: Murine liver fibrosis was developed by CCI4 treatment three times per week over a 6-week period. The CCl4-treated mice were divided into two groups: the CCl4-water group (n=8, CCl4) and the CCl4-XYXD group (n=8, CCl4+XYXD). The CCl4+XYXD mice were treated with XYXD from the beginning of the first week. The expression of inflammatory cytokines and apoptotic molecules were examined using immunohistochemistry, real-time PCR, and western blot. The intestinal epithelial cell apoptosis was examined by TUNEL staining. The tight junction-related molecules, such as ZO-1, claudin, and occludin in the gut were measured by real-time PCR. Results: In CCl4-treated mice damage of the intestinal epithelia and infiltration of inflammatory cells into the lamina propria and muscular layer were observed. Proinflammatory markers MCP-1, TNF-α, CXCL11, IL-6, and CD68 were significantly increased in the intestinal epithelia in CCI4-treated mice. The expression of pro-apoptotic molecules including Fas and Bax was increased in the intestinal epithelia in CCI4-treated mice compared with that in control. The number of TUNEL-positive intestinal epithelial cells was also markedly increased in CCl4-treated mice. The expression of the tight junction proteins including ZO-1, claudin, and occludin was significantly decreased in CCI4-treated mice compared with that in control mice. Notably, XYXD treatment ameliorated increased inflammatory markers and apoptosis-related molecules and decreased tight-junction proteins in CCl4-treated mice. Conclusion: CCl4-treatment increased expression of proinflammatory cytokines and pro-apoptotic molecules and disrupted tight junction integrity in the intestine. XYXD treatment ameliorated intestinal inflammation, cell death, and tight junction disintegrity induced by CCl4 treatment, suggesting that XYXD inhibits CCl4-mediated liver fibrosis at least in part by ameliorating the intestinal epithelial damage.