Abstract: Objective: To investigate the effects of dandelion polysaccharide on IL-6/STAT3 signaling pathway in rats with ulcerative colitis.Methods: Forty SD rats were randomly divided into four groups (n=10):control group, model group, positive control group and dandelion polysaccharide group. The ulcerative colitis model was established by treated with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The positive control group was treated with mesalazine 10 mg/kg·d and dandelion polysaccharide group was treated with dandelion polysaccharide 10 mg/kg·d. The levels of interleukin -6(IL-6), colonic myeloperoxidase (MPO) and interleukin-6 receptor (sIL-6Rα) were measured after 4 weeks of treatment. The pathological changes of colonic mucosa were observed in rats. The gene expressions of glycoprotein 130 (gp130), transcriptional activator3(STAT3) and IL-6 were detected.Results: Compared with the normal control group, the level of serum IL-6 in the model group was significantly higher than that in the control group (P<0.01). Compared with the model group, the serum levels of IL-6 in the dandelion polysaccharide group and the methacetin group were significantly decreased (P<0.01). Compared with the model group, the MPO positive density of the rats in the dandelion polysaccharide group and the methacetin group was significantly lower than that in the normal group (P<0.01). Compared with the model group, the levels of sIL-6Rα and gp130 in the rats were significantly lower than those in the model group (P<0.01). Compared with the model group, the expressions of STAT3 and IL-6 mRNA in the intestinal tissue of the rats in the dandelion polysaccharide group and the methacetin group were decreased significantly.Conclusion: Dandelion polysaccharide can decrease the level of IL-6 in rats with ulcerative colitis, regulate the expression of sIL-6Rα and gp130 protein in IL-6/STAT3 pathway, and then down-regulate the expressions of STAT3 and IL-6 mRNA in intestinal tissue of rats, alleviate the colon inflammation state, protect and repair the mucosal tissue. Dandelion polysaccharide plays a role in the treatment of ulcerative colitis.

Key words: dandelion polysaccharide, inflammatory bowel disease, rat model, IL-6/STAT3 signaling pathway, regulation