狼疮性肾炎小鼠肾组织中HMGB1、TLR4、STAT3、PCNA的表达及意义

摘要

目的 观察狼疮性肾炎小鼠肾组织中细胞因子高迁移率族蛋白1 (HMGB1)、Toll样受体4(TLR4)、信号转导和转录激活因子3(STAT3)、增殖细胞核抗原(PCNA)的表达及意义.方法 选用16周雄性BXSB小鼠(狼疮性肾炎模型,观察组)以及C57 BL/6小鼠(正常对照组)为研究对象,采用透射电镜技术观察两组小鼠肾组织超微结构改变,PAS染色观察肾小球基底膜变化,免疫组织化学法检测肾组织中的HMGB1、TLR4、PCNA蛋白,RT-PCR法检测肾组织中的HMGB1、p-STAT3 mRNA,Western blot法检测肾组织中的p-STAT3.结果 16周时,透射电镜下观察组肾组织出现明显的狼疮性肾炎病理表现,而正常对照组肾组织结构正常.与正常对照组相比,观察组小鼠肾小球基底膜明显增厚.观察组小鼠肾组织中HMGB1、TLR4、PCNA积分吸光度值以及HMGB1 mRNA、p-STAT3mRNA、p-STAT3的相对表达量均高于正常对照组(P均＜0.05).观察组小鼠肾组织中HMGB1与TLR4、TLR4与p-STAT3、HMGB1与p-STAT3、p-STAT3与PCNA、HMGB1与PCNA、HMGB1 mRNA与p-STAT3 mRNA的表达水平之间呈正相关(r分别为0.952、0.945、0.895、0.784、0.929、0.717,P均＜0.05).结论 HMGB1在小鼠狼疮性肾炎中的致炎作用,可能通过结合其受体TLR4进而激活STAT3传导途径实现的.%Objective To investigate the expression and effect of HMGB1/TLR4/STAT pathway in murine lupus nephritis. Methods The ultra-structure of renal tissue was observed by transmission electron microscope. PAS stain was used to observe the change of renal glomerulus basement membrane. The expression of HMGB1, TLR4 and PCNA protein were tested by immunohistochemistry. Detection of HMGB1 and STAT3 mRNA were performed by PCR. Western blot was used to check the expression of p-STAT3 protein. Results Compared with control group, LN group demonstrated the thickness of glomerulus basement membrane ( GBM) , fusion of foot processes partly of epithelial cell and subepithelial e-lectron-dense deposits at 16 weeks. The expression of HMGB1 mRNA and protein increased significantly in LN group, the HMGB1 protein mainly located in the cytoplasm and extracellular milieu especially in the hypertrophic glomeruli, whereas weak expression was found in the nucleus of renal tubule in control group. Compared with control group, the expression of p-STAT3 mRNA and protein significantly increased in LN group. Strong expression of TLR4 as well as PCNA protein was seen in glomeruli of LN group, whereas negative expression was found in control group. In LN group, there were positive correlation between the expression of HMGB1 and TLR4, p-STAT3, PCNA protein respectively ( r = 0. 952, 0. 895 and 0.929, P ＜ 0. 05 ) , as well as between p-STAT3 and TLR4, PCNA protein ( r = 0. 945, 0. 784, P ＜ 0. 05 ) , between the expression of HMGB1 and p-STAT3 mRNA (r =0.717, P＜0.05). Conclusion HMGB1 could activate STAT3 through combining with its cell-surface receptor-TLR4, which might contribute to the pathogenesis of lupus nephritis.