Podocin在阿霉素肾病大鼠模型肾皮质部表达及分布的时相变化

Expression and distribution of podocin in different pathological processes in adriamycin-induced nephrotic rat model

目的动态观察足细胞相关分子podocin在阿霉素肾病大鼠模型肾皮质部的表达及分布的时相变化,探讨podocin分子在蛋白尿发生发展过程中的作用。方法建立阿霉素大鼠肾病模型,实验分为模型组(阿霉素肾病大鼠24只)和对照组(正常大鼠24只)。观察1、2、4和6周各项指标的变化,包括24h尿蛋白定量、血浆白蛋白(Alb)和总胆固醇(TC)检测,光镜下观察肾组织病理改变,采用Western blot检测肾皮质部podocin的蛋白表达,采用荧光定量PCR检测肾皮质部podocin的mRNA表达,应用免疫荧光法观察podocin在肾组织中的分布。结果阿霉素肾病大鼠模型组蛋白尿持续增加,并出现低白蛋白血症、高脂血症,表现为典型的肾病综合征;模型组由微小病变逐渐发展至局灶节段性硬化;模型组podocin在肾皮质部的蛋白表达2周时开始增高,4周时明显增高,6周时仍维持在较高水平;模型组podocin在肾皮质部的mRNA表达1周时开始增高,2周时明显增高,4周后较对照组下降;模型组podocin荧光染色由正常的沿肾小球血管襻呈均匀线性分布转变为呈不连续颗粒状分布,且分布异常并进行性加重。结论Podocin在阿霉素肾病大鼠模型中蛋白和mRNA表达变化的时相不同,并且分布异常是发生蛋白尿的关键因素,推测podocin可能参与肾病病程进展的内在分子机制。

Objective To dynamicly observe the expression and distribution of podocin in different pathological mechanism of adriamycin-inducing nephrotic （ADN） rats,to explore the possible mechanisms of podocin during the occurrence and development of proteinuria.Methods The study had two groups,model group （n=24）,control group （n=24）.The changes of following indexes were observed at the 1st,2nd,4th,6th weeks.（1） Urine protein quantization of 24 hour,the levels of serum albumin and total cholesterol.（2） The histopathology detection by light microscope.（3） Protein expression of podocin in cortex of kidney detected by Western blot.（4） Examined mRNA expression of podocin in cortex of kidney by real time RT-PCR.（5） The localization of podocin in glomerular by immunofluorescence.Results （1） The model group was observed massive proteinuria,hypoproteinemia and hypercholesterolaemia.（2） In the model group minimal change disease was developed to focal segmental glomerulosclerosis observed by optical microscope and electron microscope.（3） In model group podocin protein expression increased at the 1st,2nd,4th,6th week,most obviously at the 4th week.（4） Compared with the control group,in the model group podocin mRNA expression increased at the 1st week,peaked at the 2nd week,decreased from the 4th week;（5） In model group podocin staining gradually shifted from a linear-like pattern along the capillary loops of glomerulus to a discontinuous coarse granular pattern.Conclusions During the pathological course of AND,it leads to the occurrence and development of the proteinuria and the adnormal expression and distribution of podocin may contribute to the pathological process.