[Protective role of green tea polyphenols in intestinal mucosal barrier function of mice with colitis induced by TNBS through inhibiting JAK2/STAT3 pathway].

Objective To analyze the therapeutic effect of green tea polyphenols (GTP) in mice with colitis induced by TNBS and its possible mechanism. Methods Colitis was induced by TNBS in BALB/C mice. The mice were randomly divided into GTP group (n=10) and TNBS model group (n=10). Mice in the GTP group were given GTP [0.2 mL at a dose level of 100 mg/(kg.d)] by oral gavage, and mice in the model group were given normal saline [0.2 ml/d] by gavage. Four weeks later, the mice were sacrificed. Disease activity index (DAI) and inflammatory score were evaluated by HE staining. The levels of interleukin 10 (IL-10), IL-6 and tumor necrosis factor α (TNF-α) were detected by ELISA. The expressions and localization of ZO-1 and claudin-1 were identified with immunofluorescence technique. Western blot analysis was performed to detect the expressions of ZO-1, claudin-1, p-JAK2 and p-STAT3 proteins. Results GTP decreased the DAI and inflammatory score, and reduced the levels of TNF-α and IL-6 in TNBS-induced colitis mice at three and four weeks after the administration. Meanwhile, the levels of ZO-1 and claudin-1 increased in the mice of GTP group when compared with those in model group. Western blot analysis showed that GTP down-regulated the JAK2/STAT3 signaling pathway in the intestinal mucosa. Conclusion GTP has a significant therapeutic effect on TNBS-induced colitis through down-regulating the JAK2/STAT3 signaling pathway.