Flower extract of Caragana sinica. ameliorates DSS-induced ulcerative colitis by affecting TLR4/NF-κB and TLR4/MAPK signaling pathway in a mouse model

OBJECTIVE(S): This study aimed to find out the protective effects and preliminary mechanisms of the flower extract of Caragana sinica (FEC) on dextran sulfate sodium salt (DSS)-induced colitis. MATERIALS AND METHODS: The ulcerative colitis models of mice induced by 3% DSS were established and treated with FEC. Body weight changes, disease activity index (DAI), colon histopathological score, anti-oxidant ability, and the level of inflammatory cytokines were determined. The expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) were assessed in colonic tissue by immunohistochemical staining. Western blot was used to analyze the expression of TLR4/ nuclear factor kappa-B (NF-κB) and TLR4/ mitogen-activated protein kinase (MAPK) signaling pathway-related proteins. RESULTS: FEC significantly prevented body weight loss and colonic shortening and reduced the disease activity index and histopathological score (P<0.05). Moreover, FEC treatment remarkably down-regulated the levels of myeloperoxidase (MPO), interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) and up-regulated the levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and interleukin 10 (IL-10) in the colon of DSS mice (P<0.05). Furthermore, the expression of TLR4/NF-κB and TLR4/MAPK pathway-related proteins was inhibited by FEC (P<0.05). CONCLUSION: Our findings demonstrated that FEC could serve as a potential therapeutic agent for treatment of ulcerative colitis.