“风寒湿”外邪影响Th17/Treg失衡促进类风湿关节炎病证发生的分子机制研究

Mechanistic Studies of Th17/Treg Imbalance Influenced by Exogenous Wind-cold-damp Pathogens on the Development of Rheumatoid Arthritis

目的探讨Th17/Treg细胞在类风湿关节炎(痹证)中的表达情况及“风寒湿”外邪影响痹证发生的分子机制。方法(1)雄性SD大鼠90只,随机分为正常对照组、单纯佐剂性关节炎(AIA)组和AIA风寒湿痹组,每组30只。正常对照组和单纯AIA组大鼠正常饲养;AIA风寒湿痹组每天置于人工智能气候箱内接受风寒湿刺激,14 d后单纯AIA组和AIA风寒湿痹组免疫含有热灭活结合杆菌的完全弗氏佐剂(CFA);AIA风寒湿痹组CFA免疫后风寒湿再刺激6 d。各组动物CFA免疫前1天、免疫后第6、10天,分离外周血单核细胞(PBMCs),流式细胞术检测CD4^(+)Th17和CD4^(+)CD25^(+)Foxp3^(+)Treg细胞,分析Th17/Treg细胞比例。(2)雄性SD大鼠20只,随机分为正常对照组和AIA风寒湿痹组,每组10只。正常对照组和AIA风寒湿痹组大鼠的实验条件同(1)。CFA免疫后第14天麻醉大鼠,分离PBMCs,流式细胞术检测外周血CD4^(+)T细胞pSTAT3蛋白、CD4^(+)IL-17^(+)淋巴细胞pSTAT4和pSTAT6的蛋白平均荧光强度,RT-PCR检测外周血CD4^(+)T细胞中RORγt、Foxp3、STAT3、STAT4、STAT6 mRNA的表达。结果随着AIA风寒湿痹大鼠病情的进展,外周血CD4^(+)Th17细胞比例逐渐增加,CD4^(+)CD25^(+)Foxp3^(+)Treg细胞比例逐渐降低,与同时间点单纯AIA组大鼠比较,差异具有统计学意义(P<0.05或P<0.01)。与正常对照组比较,AIA风寒湿痹组大鼠外周血CD4^(+)pSTAT3^(+)和CD4^(+)IL-17^(+)pSTAT4^(+)及CD4^(+)IL-17^(+)pSTAT6^(+)蛋白表达量显著增加,CD4^(+)T细胞中Foxp3 mRNA表达量显著降低,而RORγt、STAT3、STAT4、STAT6 mRNA表达量显著增加,差异具有统计学意义(P<0.05或P<0.01)。结论“风寒湿”外邪可能通过JAK/STAT信号通路激活Th17细胞分化,并抑制Treg细胞分化,导致Th17/Treg细胞失衡,从而促进RA病证的发生。

Objective To observe the molecular mechanism of“wind-cold-damp”(FHS)exogenous pathogenic factors and the expression of Th37/Treg cells on Bi syndrom(rheumatoid arthritis,RA).Methods(1)Ninety male SD rats were randomly and evenly assigned into normal control group,simple adjuvant-induced arthrtis(AIA)group and FHS+AIA group.Normal control group and simple AIA group were normally fed,and the FHS+AIA group was placed in an intelligent artificial climate box every day to receive FHS stimulation.After 14 days of FHS stimulation,rats in the simple AIA group and FHS+AIA group were injected complete Freud’s adjuvant(CFA)containing heat-inactivated Mycobacterium tuberculosi to establish AIA.FHS+AIA group continued to receive FHS stimulation for additional 6 days.Peripheral blood mononuclear cells(PBMCs)were isolated 1 day before,6 and 10 days after CFA immunization.Percentages of CD4^(+)Th17 and CD4^(+)CD25^(+)Foxp3^(+)Treg cells were detected by flow cytometry.(2)Twenty male SD rats were randomly and evenly assigned into normal control group and FHS+AIA group.The experimental conditions of rats in normal control group and FHS+AIA group were the same(1).On day 14 after CFA injection,rats were anesthetized and blood specimens were collected for isolation of PBMCs.Mean fluorescence intensity of pSTAT3 protein in CD4^(+)T cells,pSTAT4 and pSTAT6 proteins in CD4^(+)IL-17^(+)T cells were detected and analyzed by flow cytometry,and mRNA expression levels of RORγt,Foxp3,STAT3,STAT4,and STAT6 in CD4^(+)T cells were examined by RT-PCR.Results With the progression of the disease in FHS+AIA group of rats,the proportion of peripheral blood CD4^(+)Th17 cells gradually increased,and the proportion of CD4^(+)CD25^(+)Foxp3^(+)Treg cells gradually decreased,compared with the simple AIA group of rats at the same time point,the difference was statistically significant(P<0.05 or P<0.01).Compared with normal control group of rats,FHS+AIA group of rats showed significantly elevated fluorescent intensities of CD4^(+)pSTAT3^(+),CD4^(+)IL-17^(+)pSTAT4^(+)and CD4^(+)IL-17^(+)pSTAT6^(+)proteins in the peripheral blood,markedly decreased mRNA level of Foxp3 and significantly increased mRNA levels of RORγt,STAT3,STAT4,and STAT6 detected in CD4^(+)T cells,the difference was statistically significant(P<0.05 or P<0.01).Conclusion FHS exogenous pathogenic factors may activate the differentiation of CD4^(+)Th17 cells and inhibit the differentiation of Treg cells through the JAK/STAT signaling pathway,leading to imbalance of Th17/Treg cells,thus promoting the occurrence of RA syndrome.