Curcumin ameliorates dextran sulfate sodium-induced experimental colitis by blocking STAT3 signaling pathway

Background and aims: Although a series of studies have shown that curcumin can exert anti-inflammatory effects in colitis by inhibiting NF-kappa B activation, whether these anti-inflammatory effects of curcumin are also attributed to its ability to inhibiting STAT3 pathway has never been tested in experimental colitis to date. The purpose of the study was to investigate whether curcumin could exert its therapeutic effects in experimental colitis by inhibiting STAT3 pathway. Materials and methods: Curcumin was administered in experimental colitis induced by dextran sulfate sodium (DSS). The disease activity index (DAI) and histological score were observed. The phospho-STAT3 was assessed by western blot analysis. The DNA-binding activity of STAT3 dimers was evaluated by electrophoretic mobility shift assay (EMSA). The expression of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta was measured by enzyme-linked immunosorbent assay. Myeloperoxidase (MPO) activity was determined by using MPO assay kit. Results: A significant improvement was observed in DAI and histological score in mice with curcumin, and the increases in phospho-STAT3 activity, DNA-binding activity of STAT3 dimers, MPO activity, IL-1 beta, and TNF-alpha expression in mice with DSS-induced colitis were significantly reduced following treatment with curcumin. Conclusion: Curcumin exerts beneficial effects in experimental colitis by the suppression of STAT3 pathway, which may therefore provide a better understanding of the mechanism of action for curcumin in treating colitis. (C) 2013 Elsevier B.V. All rights reserved.