Abstract:Objective To investigate the effects of baicalein on T helper cells (Th) 1/2, obestatin and 5-hydroxytryptamine (5-HT) in rats with ulcerative colitis. Methods Forty SPF grade male SD rats were randomly divided into normal group (group N), model group (group M), sulfasalazine group (group S), and baicalein group (group B), with 10 rats in each group. The ulcerative colitis models were established in group M, S and B by trinitrobenzenesulfonic acid. After successful modeling, 0.3 g/kg sulfasalazine was given to group S by gavage, and 50 mg/kg baicalein was given to group B by gavage. Group N and group M were given the same volume of normal saline by gavage at the same time. The disease activity index (DAI) score and colon mucosa damage index (CMDI) score of rats were evaluated, and the pathological morphology of colon tissue was detected by hematoxylin and eosin staining. The protein expression of Th1 cytokine interferon-γ (IFN-γ) and Th2 cytokine interleukin-4 (IL-4) in colon tissues was detected by western blot, and the levels of obestatin and 5-HT in rat serum were detected by ELISA. Results All rats were successfully modeled. The DAI score and CMDI score were significantly increased in group M compared to those in group N (P<0.05), and significantly decreased in groups S and group B compared to those in group M (P<0.05), with group B being lower than group S (P<0.05). Pathological diagnosis showed that compared with group M and group S, group B had significant improvement in pathological state and a significant increase in goblet cells. Compared with group N, IFN-γ protein expression in colon tissue was significantly higher, while IL-4 protein expression was significantly lower in group M (P<0.05). Compared with group M, IFN-γ protein expression in colon tissue was significantly, while the IL-4 protein expression was significantly higher in group S and group B (P<0.05), and the changes in group B were more significant than those in group S (P<0.05). Compared with group N, the content of serum obestatin was significantly higher (P<0.05), while the 5-HT content was significantly lower in group M (P<0.05). Compared with group M, the content of serum obestratin was significantly increased (P<0.05), while the 5-HT content was significantly reduced in group S and group B (P<0.05), and the group B showed a significant change compared to group S (P<0.05). Conclusion Baicalein has significant therapeutic effects on ulcerative colitis rats, which can regulate Th1/2 cells, increase the content of serum obestatin, and reduce the content of 5-HT significantly.