Ox-LDL诱导人肾小球系膜细胞凋亡在慢性肾炎中的作用

The role of apoptosis of mesangial cells induced by Ox-LDL in chronic glomerular nephritis

目的 :探讨氧化低密度脂蛋白 (Ox-LDL)诱导肾小球系膜细胞凋亡的调控机制及其在慢性肾炎中的作用。方法 :通过人肾小球系膜细胞体外培养 ,采用原位末端标记和DNA凝胶电泳检测低浓度的Ox -LDL (0、 2 5、 5 0、10 0 μg/ml)对系膜细胞凋亡的影响 ,免疫组化维生素E干预前后Ox-LDL对系膜细胞Bax/Bcl- 2表达的影响 ;按血浆LDL水平 ,把有不同程度肾小球硬化的慢性肾炎患者肾标本分为LDL正常组和LDL升高组 ,分别采用DNA原位末端标记和免疫组化 ,检测肾小球细胞凋亡及Bax/Bcl- 2蛋白表达。结果 :低浓度Ox-LDL (0～ 10 0 μg/ml)以剂量依赖方式促进肾小球系膜细胞凋亡 ,并使肾小球系膜细胞Bax的蛋白表达呈时间 -剂量依赖性增加 ,P <0 0 1,Bcl- 2的蛋白表达轻度升高后呈时间 -剂量依赖性下降 ,P <0 0 1,导致Bax/Bcl- 2比值增大 ;维生素E干预后这种变化不明显 ,P >0 0 5。LDL升高组肾小球凋亡和Bax蛋白表达明显增加 ,P <0 0 1;Bcl- 2变化不明显 ,P >0 0 5 ,血LDL水平与肾小球硬化指数、凋亡指数、Bax/Bcl- 2比值有显著正相关关系。结论 :Ox -LDL能诱导肾小球系膜细胞凋亡 ;Bax/Bcl- 2比值上升可能是Ox -LDL诱导肾小球系膜细胞凋亡的重要机制 ;

Objective:To investigate the mechanism of mesangial cell apoptosis induced by Ox-LDL and its role in glomerular nephritis.Method:Human renal mesangial cells were isolated and cultured in vitro.TUNEL and a-garose gel electrophoresis were used to detect the apoptosis of mesangial cells induced by Ox-LDL at low concentration(0ug/ml-100ug/ml).immunohistochemistry was employed to detect the influence of Ox-LDL on the expression of Bax/Bcl-2 protein of mesangial cells before and after vitamin E intervention.The nephritis specimens with different degree glomerulosclerosis were divided into two groups:normal and high LDL group.The apoptosis of mesangial cells and expression of Bax/Bcl-2 protein in two groups were all detected.Result:Ox-LDL could accelerate the apoptosis of mesangial cells in dose-dependent manner at low concentration(0ug/ml-100ug/ml).The Bax protein expression increased but the Bcl-2.Both Bax and Bcl-2 protein expression did not significantly increase after intervention with vitamin E.The mesangial cell apoptosis and Bax protein expression in high LDL group were significantly change.The blood LDL level in patients with chronic nephritis had a positive correlationship to glomerular sclerosis and apoptosis and the ratio of Bax to Bcl-2.Conclusion:Ox-LDL could induce mesangial cell apoptosis at low concentration(0ug/ml-100ug/ml).The increase of ratio of Bax to Bcl-2 protein may be the important mechanism of mesangial cells apoptosis induced by Ox-LDL.Lipid abnormality may be an importanht cause of cell deletion leading to glomerulosclerosis.