Ulcerative colitis (UC) is a disease that cause chronic inflammation in colon, characterized by abdominal pain and diarrhea mixed by bloody stool. Indigo naturalis (referred to as Qing-Dai), a traditional Chinese medicine, has been widely used as an anti-ulcerative colitis regimen in clinical practice of Chinese Medicine since 1960s (Feagan et al., 2013) . However, the precise mechanisms behind its efficacy remain unknown. In this study, we aimed to investigate the effects of indigo naturalis on Th1/Th17 cell responses in UC. A dextran sulfate sodium (DSS)-induced colitis mouse model was established, and the clinical and immunologic modulations of indigo naturalis in this model were investigated. It was found that indigo naturalis attenuated DSS-induced colitis as represented by suppressing Th1 and Th17 cytokine profiles and associated genes expression, as well as reducing Th1 and Th17 cells in mesenteric lymph nodes. Indigo naturalis treatment also abated the expression of p-p38, p-ERK and p-JNK, and inhibited degradation of IκB-α in the colon of DSS-treated mice. In vitro studies also showed that indigo naturalis suppressed Th1 and Th17 cells differentiation and inhibited the phosphorylation of STAT1 and STAT3 in T cell. These findings suggest that indigo naturalis could attenuate colonic damage by modulating Th1/Th17 cell responses and indicate that indigo naturalis is an effective regimen in treatment of inflammatory bowel disease.
Keywords : Indigo naturalis; Qing-Dai; Ulcerative colitis; Th1/Th17; Mucosal healing
Acknowledgements : This study was supported by Grant from National Natural Science Foundation of China (No. 81560676) and natural research platform (No. 2016-004) of Department of Education, Guizhou Province, China.
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