Effect of curcumine in regulating the balance between regulatory T cells/helper T lymphocyte 17 via SOCS3 in inflammatory bowel disease in immature rat

Abstract

Objective To determine the therapeutic efficacy of curcumine on inflammatory bowel disease (IBD) and its underlying mechanisms. Methods The rat ulcerative colitis model was developed by using 30 g/L dextran sulfate sodium.Twenty-four young rats were divided into 4 groups: normal group, model group, curcumin 100 mg/kg group(curcumin 100 group), and curcumin 300 mg/kg group(curcumin 300 group). Curcumin was given through gastric gavage once a day for 7 days.General condition, disease activity index (DAI) and histopathological score(HPS) were evaluated.The proportions of CD4+ CD25+Foxp3+ regulatory T cells(Treg) and CD4+ IL-17+ helper T lymphocyte 17(Th17) in CD4+ T cells in rats, and spleen cells were calculated by using flow cytometry.Immunohistochemical method was performed to determine the level of SOCS3 in colon tissues. Results After curcumin administered through gastric gavage for 5 days, compared with the DAI in the model group[(7.50±0.32) scores], HPS in the curcumin 100 group[(4.00±1.10) scores] and the curcumin 300 group [(5.00±0.89) scores] significantly reduced, and the difference was significant(F=12.469, P 0.05). Compared with the model group[(6.5±1.5)%], the propotion of CD4+ CD25+Foxp3+ Treg cells in CD4+ T cells in the curcumin 100 group[(9.9±1.0)%], the curcumin 300 group [(9.3±0.7)%] and the normal group[(9.6±1.1)%]was obviously upregulated(F=16.635, P 0.05). Compared with the model group[(3.5±1.4)%], the propotion of CD4+ IL-17+ Th17 cells in CD4+ T cells in the curcumin 100 group[(2.0±0.9)%], the curcumin 300 group [(1.2±0.6)%] and the normal group[(2.0±0.9)% ] was downregulated(F=5.155, P 0.05). There was no obvious difference between the curcumin 100 group and the curcumin 300 group in these indicators respectively(all P>0.05). Conclusions Curcumin probably attenuates IBD severity, reduces inflammation and regulates the balance of Treg/Th17 through the inhibition of SOCS3 expression. Key words: Inflammatory bowel disease; Curcumine; SOCS3; Regulatory T cells; Helper T lymphocyte 17