IL-17在炎性肠病中的表达及其与LPS协同诱导肠上皮细胞表达IL-8的作用机制

Expression of IL-17 in inflammatory bowel disease and synergistic action of IL-17 and LPS on IL-8 expression in intestinal epithelial cells

目的:探讨IL-17细胞因子在TNBS诱导的炎性肠病动物模型中的表达变化,明确IL-17和脂多糖(LPS)在诱导HT-29肠上皮细胞IL-8表达中的协同作用及细胞内信号机制.方法:探讨IL-17及其受体在TNBS炎性肠病模型中的表达变化,利用细胞培养、FASC、Real-time PCR、酶联免疫吸附(ELISA)、Western blot等技术,观察IL-17及不同剂量LPS干预人肠上皮细胞(HT-29细胞)后细胞因子IL-8在蛋白水平的表达,以及IL-17受体(IL-17Ra)在mRNA水平的表达变化及引起上述效应的细胞内信号传导机制.结果:TNBS诱导的炎性肠病动物模型中IL-17以及IL-17Ra显著升高(P<0.03);炎症介质IL-17能与一定浓度范围内的LPS协同促进IL-8的表达(2187.61±132.42vs2634.27±134.63,P=0.01),增强NF-κB信号通路的活化,促进炎症反应.但随着LPS剂量升高,LPS本身诱导IL-8表达的活性降低,且与IL-17的协同作用消失(1841.43±50.38vs1685.67±71.47,P=0.03).结论:IL-17与低浓度的LPS可协同促进HT-29细胞炎症介质的表达,但与高浓度LPS联合时,两者无协同效应.

AIM：To investigate the expression of interleukin-17（IL-17）in inflammatory bowel disease（IBD）in a mouse model and to examine the synergistic reaction of IL-17 and lipopolysaccharide（LPS）on interleukin-8（IL-8）expression in intestinal epithelial cells（HT-29 cells）.METHODS：A mouse model of inflammatory bowel disease was induced with TNBS to detect the expression of IL-17 and its receptor IL-17Ra in IBD.HT-29 cells were treated with IL-17 and/or different concentrations of LPS to examine their synergistic action on the expression of IL-8 mRNA and protein by FACS,real-time PCR,ELISA,and Western blot.RESULTS：The expression of IL-17 and IL-17Ra in IBD was significantly increased（both P 0.05）.IL-17 and low doses of LPS showed a synergistic action on IL-8 expression in HT-29 cells（2187.61±132.42 vs 2634.27±134.63,P=0.01）by activating NF-？B and promoting inflammation.However,high doses of LPS reduced the levels of IL-8,and their synergistic action with IL-17 disappeared（1841.43±50.38 vs 1685.67±71.47,P=0.03）.CONCLUSION：IL-17 has a synergistic action with low,but not high doses of LPS on the expression of inflammatory mediators in HT-29 cells.