Ethnopharmacological relevance: Ulcerative colitis (UC) is one of non-specific inflammatory bowel disease that mainly affects the colon. Recently, UC has become a significant social and economic problem worldwide. Baitouweng decoction (BD), a traditional Chinese medicine described in the "Treatise on Febrile Diseases", has been used for centuries to treat intestinal diseases. However, its underlying mechanism remains largely unexplored.
Aim of study: In this study, we aimed to investigate the effect of BD on autophagy for repairing the colonic barrier in DSS-induced colitis mice and explored its role in regulating the autophagic signaling pathway AMPK/mTOR.
Materials and methods: Mice with colitis were treated with 3% dextran sulfate sodium (DSS) for 7 days. The effectiveness of BD in treating DSS-induced colitis was evaluated through body weight, disease activity index (DAI), colon length, pathological changes, organ index, and proportion of blood cells. Moreover, intestinal epithelial permeability was analyzed by examining FITC-dextran leakage, the bacterial load of mesenteric lymph nodes (MLNs), and bacterial infiltration of colon tissues. Barrier function was evaluated by assessing the number and proportion of colonic goblet cells and the expression of tight junction proteins, including ZO-1, claudin-1, and occludin. Furthermore, the levels of autophagy were assessed by examining the number of autophagosomes and the expression of the autophagy-related proteins LC3, Beclin1, and P62. Additionally, network pharmacology research was conducted to analyze the potential mechanisms underlying the medicinal effects, as indicated by the role of AMPK/mTOR in regulating the autophagic signaling pathway.
Results: BD improved colitis symptoms in mice by restoring body weight and colon length and reducing inflammatory cell infiltration. Additionally, BD decreased the diffusion of FITC-dextran and bacterial translocation in MLNs, as well as bacterial infiltration of the colonic mucosa. The number and proportion of colonic goblet cells, the expression of ZO-1, Claudin-1, and Occludin, and the levels of autophagy were also increased by BD. Network pharmacology analysis suggested that BD might affect intestinal autophagy through the AMPK signaling pathway, which was confirmed by the activation of AMPK phosphorylation and the downregulation of mTOR expression following BD treatment.
Conclusion: Our study demonstrated that BD repaired the intestinal epithelial barrier in DSS-induced colitis mice by activating AMPK phosphorylation and inhibiting mTOR expression to promote autophagy.
Keywords: AMPK/mTOR; Autophagy; Baitouweng decoction; Colitis; Intestinal barrier; Tight junction.
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