a-生育酚抑制高糖诱导大鼠系膜细胞AP-1活性及TGFB_(1)表达

a-Tocopherol Inhibits Activator Protein-1 Binding and TGF-β_(1) Expression Induced by High Glucose in Rat Mesangial Cells

目的 研究α 生育酚对高糖诱导肾小球系膜细胞转录激活蛋白 1(AP 1)和转化生长因子 β1(TGF β1)的影响 ,探讨抗氧化剂治疗糖尿病肾病的机制。方法 采用凝胶迁移率实验 (Gelshiftassay)和超迁移率实验(Gelsupershiftassay)检测不同浓度及不同时间下葡萄糖对系膜细胞AP 1活性的影响、AP 1二聚体中Jun和Fos成分的变化、Western杂交检测TGF β1蛋白表达水平以及抗氧化剂α 生育酚对上述指标的影响。结果 高糖呈浓度和时间依赖性激活系膜细胞AP 1活性 ,AP 1二聚体中JunD、Fos参与这一作用。同时 ,葡萄糖增加系膜细胞TGF β1蛋白表达。加入α 生育酚预处理系膜细胞后 ,葡萄糖诱导的AP 1活性和TGF β1表达水平降低。结论 α 生育酚抑制高糖诱导的系膜细胞AP 1活性及TGF

Purpose To study the effects of α tocopherol on activator protein 1(AP 1)binding and TGF β 1 expression induced by high glucose in rat mesangial cells and further to clarify the molecular mechanism of antioxidant in treating diabetic nephropathy. Methods AP 1 binding of the rat mesangial cells exposed to high glucose was detected by gel shift assay.The Jun,Fos compositions of AP 1 dimer were determined by supershift assay.Protein expression of TGF β 1 was detected by Western blot.Additionally,the effects of α tocopherol on AP 1 binding and TGF β 1 expression induced by glucose in rat mesangial cells were also studied. Results High glucose stimulated AP 1 binding of mesangial cells in time and dose dependent manners .This AP 1 binding increase involved JunD and Fos as shown by gel supershift.Glucose also increased protein expression of TGF β 1 at same time.The increased AP 1 binding and TGF β 1 were inhibited with pretreatment with α tocopherol in glucose treated mesangial cells. Conclusions This study suggests that α tocopherol can significantly inhibit AP 1 activity and TGF β 1 expression by glucose in rat mesangial cells,which may be one of its antioxidation mechanisms to retard diabetic nephropathy.