Effects of Qing Hua Chang Yin on lipopolysaccharide-induced intestinal epithelial tight junction injury in Caco-2 cells

Disruption of the intestinal mucosal barrier integrity is a pathogenic process in inflammatory bowel disease (IBD) development, and is therefore considered a drug discovery target for IBD. The well-known traditional Chinese formulation Qing Hua Chang Yin (QHCY) has been suggested as a potential therapeutic agent for the treatment of ulcerative colitis. However, the possible underlying molecular mechanisms regarding its therapeutic effect remain unclear. Consequently, the present study investigated the effects of QHCY on lipopolysaccharide (LPS)-induced loss of intestinal epithelial barrier integrity in vitro using the Caco-2 cell model of intestinal epithelium. QHCY reversed the LPS-induced decrease in transepithelial electrical resistance and significantly alleviated the increased fluorescently-labeled dextran 4 flux caused by LPS. Moreover, QHCY upregulated the mRNA and protein expression levels of occludin, zona occludens-1 and claudin-1 in LPS-exposed Caco-2 cells. In conclusion, QHCY was able to protect intestinal epithelial barrier integrity following an inflammatory insult; the protective effects of QHCY may be mediated by modulation of the expression of tight junction proteins.