Abstract: The objective of this study was to elucidate whether baicalin reduces colonic inflammation in a mice colitis model through inhibition of the TLRs/MyD88 signaling pathway.C57BL/6 mice were randomized into control group,DSS group (administered with 3.5% DSS solution) and baicalin group (administered with 3.5% DSS solution and orally administered with baicalin,30 mg/kg body weight).The disease activity index (DAI) score and histological score were evaluated.Myeloperoxidase activity was detected and colonic mucosal histological changes were observed by HE staining.The protein expression levels of Tumornecrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels in colonic tissue were determined by ELISA.The mRNA expression levels of TLR2,TLR4 and MyD88 in colonic tissue were detected by Real-time PCR.Compared with the DSS group,the baicalin-treated group showed significant decreases in DAI,histological score,myeloperoxidase activity, expressions levels of TNF-α protein,IL-6 protein,TLR2 mRNA,TLR4 mRNA and MyD88 mRNA.Collectively,these findings highlighted that baicalin had significant therapeutic effects on DSS-induced colitis and the anti-inflammatory actions of baicalin may involve inhibition of the TLRs/MyD88 signaling pathway.

Key words: baicalin, inflammatory bowel diseases, TLRs/MyD88 signaling pathway