基于TLR4/MyD88/TRAF6信号通路探究电针对类风湿关节炎大鼠滑膜组织的影响

Study of the effect of electroacupuncture on synovial tissues in rats with rheumatoid arthritis based on TLR4/MyD88/TRAF6 signaling pathway

目的观察电针干预通过调控Toll样受体4(Toll-like receptor 4,TLR4)/髓样分化因子88(myeloid differentiation primary response protein 88,MyD88)/肿瘤坏死因子受体相关因子6(tumor necrosis factor receptor-associated factor 6,TRAF6)通路对类风湿关节炎大鼠滑膜组织的影响,探究TLR4/MyD88/TRAF6信号通路作为电针干预新靶点的可能性。方法将48只Wistar大鼠随机分为健康组、模型组、电针组和电针通路激活组,每组12只。制备类风湿关节炎大鼠模型,术后采用关节炎指数评分将符合类风湿关节炎诊断标准的大鼠进行后续实验,同时采用关节炎指数评估干预前后关节炎的改善情况。采用苏木精-伊红(hematoxylin-eosin,HE)染色法检测4组大鼠关节损伤及滑膜组织状况,用酶联免疫吸附法(enzyme-linked immunosorbent assay,ELISA)检测关节液肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)和滑膜组织增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)的含量,用流式细胞仪检测软骨细胞凋亡率。采用荧光定量聚合酶链式反应(polymerase chain reaction,PCR)和蛋白印迹(Western blot,WB)法检测4组大鼠滑膜组织TLR4、MyD88、TRAF6 mRNA蛋白的表达。结果健康组关节结构完整无病变;与健康组比较,模型组大鼠关节结构不完整,出现滑膜增生,关节炎指数评分显著升高(P<0.05),TNF-α、IL-1β和PCNA的含量、软骨细胞凋亡率及滑膜组织中TLR4、MyD88和TRAF6 mRNA蛋白的表达均显著升高(P<0.05);与模型组比较,电针组关节结构相对完好,关节炎指数评分显著降低(P<0.05),TNF-α、IL-1β和PCNA的含量、软骨细胞凋亡率及滑膜组织中TLR4、MyD88和TRAF6 mRNA蛋白的表达均显著降低(P<0.05);与电针组比较,电针通路激活组关节炎指数评分显著升高(P<0.05),TNF-α、IL-1β和PCNA的含量、软骨细胞凋亡率及滑膜组织中TLR4、MyD88和TRAF6 mRNA蛋白的表达均显著升高(P<0.05)。结论电针干预可通过调控TLR4/MyD88/TRAF6信号通路,改善类风湿关节炎,并保护滑膜组织。

Objective To observe the effect of electroacupuncture on synovial tissues in rats with rheumatoid arthritis(RA)by regulating the signaling pathway Toll-like receptor 4(TLR4)/myeloid differentiation primary response protein 88(MyD88)/tumor necrosis factor receptor-associated factor 6(TRAF6)and discuss the possibility of this signaling pathway as a novel target for electroacupuncture intervention.Method Forty-eight Wistar rats were randomized into a healthy group,a model group,an electroacupuncture group,and an electroacupuncture+pathway activation group,with 12 rats in each group.The RA rat models were established.After the modeling operation,the rats whose arthritis index score met the RA diagnosis criteria continued the following experiments.The arthritis index was used to evaluate the improvement in arthritis after intervention.Hematoxylin-eosin(HE)staining was used to examine joint damage and synovial tissues of the four groups of rats;the enzyme-linked immunoassay(ELISA)was used to detect the contents of tumor necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)in the synovial fluid and the content of proliferating cell nuclear antigen(PCNA)in the synovial tissues;flow cytometry was used to determine the apoptosis rate of chondrocytes.The mRNA and protein expression levels of TLR4,MyD88,and TRAF6 in the synovial tissues were detected using the fluorescence quantitative polymerase chain reaction(PCR).Result In the healthy group,the joint structure was intact and showed no lesions.Compared with the healthy group,the joint structure was incomplete,synovial hyperplasia appeared,and the arthritis index score increased significantly in the model group(P<0.05),together with notable increases in the contents of TNF-α,IL-1β,and PCNA,chondrocyte apoptosis rate,and TLR4,MyD88,and TRAF6 mRNA and protein expression in the synovial tissues(P<0.05).Compared with the model group,the joint structure was relatively intact,and the arthritis index score decreased markedly in the electroacupuncture group(P<0.05),together with significant decreases in the contents of TNF-α,IL-1β,and PCNA,chondrocyte apoptosis rate,and TLR4,MyD88,and TRAF6 mRNA and protein expression in the synovial tissues(P<0.05).Compared with the electroacupuncture group,the arthritis index score was significantly higher in the electroacupuncture+pathway activation group(P<0.05),and the contents of TNF-α,IL-1β,and PCNA,chondrocyte apoptosis rate,and TLR4,MyD88,and TRAF6 mRNA and protein expression in the synovial tissues all increased significantly(P<0.05).Conclusion Electroacupuncture intervention can improve RA and protect synovial tissues by regulating the TLR4/MyD88/TRAF6 signaling pathway.