Modified Gegen Qinlian decoction ameliorates DSS-induced chronic colitis in mice by restoring the intestinal mucus barrier and inhibiting the activation of γδT17 cells

Background Current therapeutics for ulcerative colitis (UC) have limitations. Classical Formula Gegen Qinlian decoction (GQD) is derived from Shang Han Lun and has a long history of treating gastrointestinal diseases such as diarrhea and UC. Nevertheless, the exact mechanism of it needs to be further clarified. Purpose We aimed to investigate the treatment effects of modified GQD (MGQD) on dextran sodium sulfate (DSS)-induced chronic colitis in mice and conduct further exploration of its underlying mechanisms. Methods The protective effect of MGQD was estimated in a DSS-induced chronic colitis mouse model. Model evaluation included body weight, disease activity index (DAI) score, colon length and histopathology. Alcian Blue/Phosphoric Acid Schiff (AB/PAS) staining, transmission electron microscopy (TEM), immunofluorescence and real time‒PCR (RT-PCR) were used to assess goblet cell function. ELISA, flow cytometry and immunofluorescence were applied to estimate the immunoinflammatory status. Western blot was performed to test the protein expression levels of relevant pathways and related receptors. All experiments were conducted in duplicate. Results MGQD alleviated DSS‑induced chronic colitis symptoms in mice, protected goblet cell function and restored the intestinal mucus barrier. Furthermore, MGQD efficiently suppressed the abnormal immune inflammatory response and the activate of γδT17 cells and NLRP3 inflammasome. Conclusion The mechanisms by which MGQD protects against DSS-induced chronic colitis may involve restoring goblet cell function, repairing the intestinal mucus barrier, and modulating the immune inflammatory response. More importantly, MGQD inhibited NLRP3 inflammasome-associated signaling pathway activation, which consequently reduced the activation of γδT17 cells.