Chinese Patent Medicine Ameliorate Ulcerative Colitis in Mice by Restoring the Th17/Treg Balance

Background and Objective In China, Weichang'an Pill (WCAP) is a drug marketed for mild and moderate active ulcerative colitis (UC) but its mechanism is unknown. In the present study, the anti‐inflammatory mechanism of WCAP was investigated. Methods Dextran sulfate sodium (DSS) was used to induce UC in mice, which were divided into 4 groups ( n = 6), control, DSS, WCAP, and mesalazine. Pure water, WCAP, or mesalazine suspension was administered by gavage. UC severity was evaluated based on body weight, disease activity index (DAI), colon length, and colonic histological score. Percentage of Th17 and Treg cells and cytokine and transcription factor (TF) levels in colonic tissues were detected using flow cytometry, ELISA, IHC, and qRT‐PCR, respectively. Results Compared with the DSS group, body weight, DAI, colon length, and histological score were significantly improved in the WCAP group, and the Treg/Th17 ratio in the spleens and mesenteric lymph nodes (MLNs) of UC mice was similar in WCAP and control groups. In the WCAP group, IL‐6, IL‐1β, TNF‐α, IL‐17A, STAT3, P‐STAT3, ROR‐γt mRNA, and P‐NF‐κB p65 levels and number of ROR‐γt‐positive cells in colonic tissues were decreased; however, TGF‐β1, IL‐10, and Foxp3 mRNA levels and number of Foxp3‐positive cells were increased. Statistical difference among indicators was not found between mesalazine and WCAP groups ( p > 0.05). Conclusions WCAP significantly improved body weight, DAI, colon length, and histological score in UC mice and demonstrated effects similar to mesalazine. The anti‐inflammatory mechanism may involve the recovery of Th17/Treg balance and pro/anti‐inflammatory cytokine and TF regulation.