燃煤砷暴露对人体T细胞增殖能力的影响及其机制探讨

目的 探讨燃煤砷暴露对人体T细胞增殖能力的影响及其作用机制.方法 采集贵州省燃煤污染型砷中毒病区居民及非病区居民外周血,按<地方性砷中毒诊断标准>(WS/T 211-2001)分为暴露组(17例)、轻度砷中毒组(35例)、中度砷中毒组(38例)、重度砷中毒组(19例)及对照组(35例).采用四甲基偶氮唑盐(MTT)比色法检测T细胞刺激指数;钙离子荧光探针(Fiuo-3/AM)染色流式细胞术检测外周血单个核细胞(PBMC)钙离子指数(IECa2+);电泳迁移率改变实验(EMSA)检测PBMC活化T细胞核转录因子(NF-AT)结合DNA的活性.结果 经刀豆蛋白A(ConA)刺激后,暴露组及轻、中、重度砷中毒组刺激指数(1.315±0.962、1.611±1.224、1.114±0.545、1.289±0.875)均低于对照组(2.322±1.241,P＜0.01).经抗CD3单克隆抗体(McAb)刺激后,暴露组及轻、中、重度砷中毒组刺激指数(0.997±0.177、1.103±0.291、1.007±0.221、0.957±0.205)亦均低于对照组(1.842±0.429,P＜0.01).轻、中、重度砷中毒组PBMC经抗CD3 McAb处理后,IECa2+(110.130±49.637、92.429±31.191、77.640±35.372)均显著低于对照组(145.986±59.450,P＜0.01);中、重度砷中毒组IECa2+亦均显著低于暴露组(121.337±46.410,P＜0.05).轻、中、重度砷中毒组PBMC内NF-AT结合DNA活性(1.354±0.446、1.290±0.291、1.159±0.411)均显著低于对照组(1.722±0.291,P＜0.01)和暴露组(1.611±0.294,P＜0.05).结论 燃煤砷暴露町导致人体T细胞刺激指数下降、PBMC内IECa2+减少及NF-AT结合DNA的活性降低,表明砷可抑制人体T细胞增殖能力,其原因可能与砷对T细胞受体(TCR)/CD3信号转导途径的影响有关.

Influence of coal-arsenic exposure on human T cells proliferation and its mechanism

Objective To explore the influence of coal-arsenic exposure on human T cells proliferation and its mechanism.Methods Blood samples colleoted from individuals which lived in arsenism area of coal-burning type and non-arsenism area in Guizhou Province were divided into exposed group(17),mild(35),moderate(38) and severe arsenism group(19)and control group(35)according to Diagnosis Smndard for Endemic Arsenism (WS/T 211-2001).T cell stimulation index wag determined by methyl thiazolyl tetrazolium(MTT)colorimetric method.The intracellular Ca2+ exponential(IECa2+)in peripheral blood mononuclear cell(PBMC)was analyzed by Fho-3/AM dye and flow cytometry.DNA binding activity of actively T cells nuclear factor(NF-AT)in PBMC was evaluated by electrophoretie mobility shift assay(EMSA).Results Concanavalin A(ConA)stimulation decreased the T cells stimulation indexes in exposed group,mild,moderate and severe arsenism groups(1.315±0.962, 1.611±1.224,1.114±0.545,1.289±0.875)compared with control group(2.322±1.241),all the differences being statistically significant(P＜0.01).After stimulated by anti-CD3 monoclonal antibody(McAb),the T cells stimulation index in exposed group,mild,moderate and severe arsenism group(0.997±0.177,1.103±0.291,1.007±0.221, 0.957±0.205) were lower than that of control group(1.842±0.429,P ＜ 0.01 ). IECa2+ of PBMC after treated by anti-CD3 McAb in mild,moderate and severe arsenism group( 110.130±49.637,92.429±31.191,77.640± 35.372) were lower compared with control group(145.986±59.450,P ＜0.01 ). Moreover,IECa2+ in moderat and severe arsenism group were lower than exposed group(121.337±46.410,P ＜ 0.05). DNA binding activity of PBMC NF-AT in mild,moderate and severe arsenism group(1.354±0.446,1.290±0.291,1.159±0.411 ) were lowered than that of control group(1.722±0.291,P ＜ 0.01) and exposed group(1.611±0.294,P ＜ 0.05). Conclusions The coal-arsenic exposure can reduce the human T cells stimulation indexes,IECa2+ in PBMC and the DNA binding activity of NF-AT. It suggest that arsenic may suppress the proliferation ability of human T cells,which may be partly related to the influence of arsenic on T cell receptor(TCR)/CD3 signal transduetion pathway.