Research on the Effect and Mechanism of Qingchang Huashi Recipe on Relieving Colitis in Mice through AhR/IL-22

OBJECTIVE  To explore the therapeutic effect of Qingchang Huashi recipe on colitis model mice, and explore from the perspective of aromatic hydrocarbon receptor(AhR), to explore the effect of Qingchang Huashi recipe on IL-22 secretion and mucin and tight junction protein expression, and to explain alleviate the mucosal damage mechanism of colitis model mice, so as to provide objective basis for clinical application and drug research and development. METHODS  The mouse model of colitis was established by DSS, the body mass, fecal shape, occult blood and DAI score of disease activity index were observed every day. The colon length of mice was measured after administration, and the colonic pathology was observed by HE staining. qPCR was used to detect the mRNA of IL-1β, TNF-α, IL-6 and AhR in colon tissue. The expression levels of colonic mucin(MUC-2), AhR, cytochrome 4501A1(CYP1A1), interleukin-22(IL-22) and tight junction protein (Claudin4) were detected by Western blot. RESULTS  Compared with the normal group, the DAI score of the model group increased(P < 0.01), the length of colon shortened(P < 0.01), the pathological damage of colonic mucosa was severe, the mRNA expression of AhR decreased(P < 0.05), the mRNA expression of IL-1 β, TNF-α and IL-6 increased (P < 0.05, P < 0.01). The expressions of MUC-2, AhR, CYP1A1, IL-22 and Claudin4 decreased(P < 0.05). Compared with the model group, the DAI score of mesalazine group and Qingchang Huashi Recipe group decreased(P < 0.01), the length of colon lengthened(P < 0.01), the pathological condition of colonic mucosa improved, the mRNA expression of IL-1β, TNF-α and IL-6 decreased (P < 0.05, P < 0.01). The expressions of MUC-2, CYP1A1, Claudin4 protein increased(P < 0.01). Compared with the model group, the mRNA expression of AhR increased(P < 0.05). The expression of AhR and IL-22 protein in Qingchang Huashi Recipe group increased(P < 0.01). Compared with the Qingchang Huashi Recipe group, the DAI score of the Qingchang Huashi Recipe+TMF group increased(P < 0.01), the length of colon was shortened(P < 0.05), the pathological damage of colonic mucosa was serious, the mRNA expression of IL-1β, TNF-α, IL-6 increased(P < 0.01), the expressions of MUC-2, AHR, CYP1A1, IL-22 and Claudin4 decreased(P < 0.01). CONCLUSION  Qingchang Huashi Recipe can activate AhR, to up-regulate CYP1A1 protein, promote the production of IL-22, inhibit the level of inflammation, increase the expression of mucin and tight junction protein, and relieve colitis.