Anemoside B4 prevents acute ulcerative colitis through inhibiting of TLR4/NF-κB/MAPK signaling pathway

Anemoside B4 (B4) is a compound extracted from Pulsatilla chinensis(P. chinensis). Pharmacological studies have proved that it has certain anti-inflammatory activity. Acute ulcerative colitis (ulcerative colitis) is a non-specific inflammatory disease whose pathogenesis is not completely known, and there is no effective drugs. The purpose of this study was to investigate the protective effect of B4 on ulcerative colitis and its mechanism. In this study, the C57BL/6 mice model of ulcerative colitis was established by DSS [3% (w/v)] and treated with intraperitoneal injection of B4 and oral administration of mesalazine, respectively. During the experiment, the clinical symptoms of the mice were scored by the disease activity index (DAI). Histopathological changes were observed by HE staining. In addition, the effect of LPS on Raw264.7 cells was also studied. In vivo studies showed that B4 could prevent DSS-induced colitis mice from losing weight, shortening colon length and improving pathological changes of colon tissues. B4 significantly reduced levels of inflammatory cytokines IL-1β, IL-6, and TNF-α in colon tissues. In vitro experiments, B4 was almost nontoxic to Raw264.7 cells and could protect the Raw264.7 cells induced by LPS. In terms of mechanism, B4 significantly inhibited the activation of the TLR4 signaling pathway induced by DSS and down-regulate the expression of key proteins in the TLR4/NF-κB/MAPK signaling pathway in Raw264.7 cells induced by LPS. These findings suggest that the inhibition of B4 on ulcerative colitis may be through the TLR4/NF-κB/MAPK pathway. Therefore, B4 may be used as a potential drug for the treatment of ulcerative colitis.