The Effects of Rheum Tanguticum Polysaccharide on the Polarization of Th1 and Th2 Cells in TNBS-Induced Colitis in Murine

Inflammatory bowel diseases (IBDs) are chronic inflammatory intestinal disorders that are characterized by thickened colon walls, colon ulcerations, including two forms of ulcerative colitis (UC) and Crohn's disease (CD). UC and CD share some similar clinico-pathological characteristics but their causes are opposite. The imbalance in cytokinesis produced by Th1 and Th2 cells, the subunit of CD4(+) T cells, plays a key role in the development of IBDs. Although traditional treatment for IBDs is effective to some patients, it has numerous adverse-effects such as immuno-depression. In our previous study we found some therapeutic effects of Rheum tanguticum polysaccharide (RTP) on CD. Our present investigation focuses on the comparison of the effects of RTP (200 mg·kg(-1), once a day for five days) on UC induced by trinitrobenzene sulfonic acid (TNBS)/ethanol in BALB/c mice and CD induced by TNBS in SD rats. The mechanism of RTP was investigated by using immuno-histochemistry, Elisa assay, flow cytometry and western-blot analysis. Our results showed that RTP had significant therapeutic effects on both UC and CD. The ulcerative index and colon weight were significantly attenuated after RTP treatment while MPO activity in RTP-treated animals was markedly lower than that in the animals of TNBS administration (P<0.05, P<0.01). RTP also showed significant inhibitory effects on the expansion of CD4+T cells simultaneously improving the imbalance of Th1 and Th2 polarization (P<0.01). In conclusion, RTP appears to poses all the pre-requisites to be applied in therapeutic intervention, thus, offering a hope for effective treatment for IBDs.