Modified Gegen Qinlian decoction ameliorated ulcerative colitis by attenuating inflammation and oxidative stress and enhancing intestinal barrier function in vivo and in vitro

Ethnopharmacological relevance: Modified Gegen Qinlian decoction (MGQD), which was first documented in Treatise on Febrile Disease, is recognized as a classic prescription to treat ulcerative colitis (UC). However, its protective mechanism against UC remains to be fully elucidated.Aim of the study: To explore the impact and the potential molecular mechanism of MGQD on dextran sodium sulfate (DSS)-induced UC mice and tumor necrosis factor alpha (TNF-alpha)-induced Caco-2 cell monolayer model of intestinal barrier.Materials and methods: The chemical components of MGQD and MGQD drug containing serum (MGQD-DS) were characterized by LC-MS/MS. The therapeutic effect of MGQD on DSS-induced UC was evaluated based on body weight, disease activity index (DAI), colon length, colonic histopathological injury, inflammatory cytokines, oxidative stress response and intestinal barrier function. Cell Counting Kit (CCK)-8 assay was applied to detect the effect of MGQD-DS on the viability of Caco-2 cells. Additionally, TNF-alpha-induced Caco-2 cell monolayer model of intestinal barrier was established in vitro. The Caco-2 cell monolayers were administered blank serum or MGQD-DS to observe the effects of MGQD-DS on transepithelial electrical resistance (TEER), permeability of fluorescein isothiocyanate (FITC)-dextran, inflammatory cytokines, oxidative stress indicators and intestinal epithelial barrier (IEB).Results: MGQD significantly improved symptoms and pathological damage in UC mice by downregulating the expression of interleukin (IL)-1 beta and malondialdehyde (MDA), attenuating the loss of goblet cells and the destruction of intestinal epithelial ultrastructure, and upregulating the expression of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), zonula occludens-1 (ZO-1), Occludin, Claudin-1 and E-cadherin. In vitro, MGQD-DS significantly reduced the flux of FITC-dextran, increased the TEER, inhibited the expression of IL-21, IL-17A and MDA, and promoted the expression of IL-4, IL-10, transforming growth factor-beta (TGF-beta), SOD, CAT, GSH, Occludin and E-cadherin in TNF-alpha-induced Caco-2 cell monolayer model of intestinal barrier.Conclusion: MGQD can ameliorate DSS-induced UC mice and TNF-alpha-induced Caco-2 cell monolayer model of intestinal barrier, and the protective effect is related to its inhibition of inflammation, alleviation of oxidative stress, and repair of intestinal barrier damage.

Automated summary

Through experiments, it was found that a drug called MGQD can alleviate ulcerative colitis, and its mechanism of action may be related to the inhibition of inflammation, alleviation of oxidative stress, and repair of intestinal barrier damage.