IL-10-dependent Effect of Chinese Medicine Abelmoschus manihot on Alleviating Intestinal Inflammation and Modulating Gut Microbiota

Inflammatory bowel disease (IBD) is a recurrent disease associated with a potential risk of colorectal cancer. Abelmoschus manihot (AM), a Chinese herbal medicine, is known to alleviate IBD. However, its mechanism of action requires further clarification. Here, we focused on the role of IL-10 and the gut microbiota in the mechanism of action of AM. The effects of AM on intestinal inflammation, mucus production, and gut microbes were evaluated in dextran sodium sulfate (DSS)-induced acute and chronic IBD models and in IL-10-deficient mice (IL-10(-/-)). AM exhibited protective effects on acute and chronic models of IBD in wild-type mice by restoring body weight and colon length, promoting IL-10 secretion, and decreasing TNF-a levels. Moreover, AM alleviated inflammatory infiltration, increased mucin 2 transcription, and increased the number of goblet cells in the colon. On the contrary, these effects were diminished in IL-10(-/-) mice, which implied that the effect of AM on intestinal inflammation is IL-10-dependent. A gut microbial sequencing analysis showed that gut microbial dysbiosis was modulated by AM intervention. The regulatory effects of AM on Eggerthellaceae, Sutterellaceae, Erysipelotrichaceae, Burkholderiaceae, Desulfovibrionaceae, and Enterococcaceae were dependent on IL-10. These results revealed that AM ameliorated IBD and modulated gut microbes by promoting IL-10 secretion, indicating that AM has the potential to improve IBD and that AM is IL-10-dependent.