目的　观察 podocin在大鼠氨基核苷嘌呤霉素肾病模型中的表达和分布的改变 ,探讨其在蛋白尿发生中的可能作用。方法　通过一次性腹腔注射氨基核苷嘌呤霉素 (PAN)建立大鼠肾病模型 ,分别于注射后 1,3,10 ,2 0d处死大鼠 ,每次 6只。对照组注射等量的生理盐水。应用光镜、电镜观察肾脏病理改变 ,应用免疫荧光染色结合图像分析、半定量RT PCR的方法 ,检测肾组织的podocin的表达。结果　①PAN注射后第 3天 ,大鼠 2 4h尿蛋白的排泄量逐渐增加 ,第 10天达高峰 ,较对照组差异有显著性 (P <0 .0 1) ;第 2 0天 ,模型组大鼠 2 4h尿蛋白排泄逐渐恢复 ,但仍高于对照组 (P <0 .0 5 )。②PAN肾病模型第 3、10天 ,透射电镜显示足细胞足突融合。③与对照组比较 ,肾小球podocin的表达在PAN注射后第 1天出现下调 ,第 3、10天显著下调 ,第 2 0天podocin的表达逐渐恢复 ,但仍低于对照组 (P <0 .0 1)。④Podocin在正常大鼠肾小球沿毛细血管襻 ,呈均匀连续的线样分布。肾病模型第 1天 podocin的分布变得不均匀 ,局部呈颗粒状分布 ;第 3天 podocin的分布呈现弥散性的颗粒状 ;第 10天podocin呈粗大的颗粒状分布。第 2 0天podocin的分布逐渐恢复为线样。⑤肾病模型第 1、3、10天PodocinmRNA水平较对照组表达略有增强 ,第 2 0天恢复

Objective To investigate the expression and distribution of podocin and its role in the development of proteinuria in rats with puromycin aminonucleoside (PAN) nephropathy. Methods The nephropathy model was established by a single injection of PAN. The rats in the Model group were sacrificed on days 1, 3, 10 and 20 after PAN injection. The renal histological changes were observed under light and electron microscopes. The indirect immunofluorescence staining and semiquantitative reverse transcription PCR were used to detect the expression of podocin. Six rats which received normal saline with the same volume as the Model group served as the Control group. Results ① The proteinuria which was gradually increased 3 days after PAN injection reached a peak on day 10 (P< 0.01) and decreased on day 20 but was still greater than that of the Control group (P< 0.05). ② In the process of development of PAN nephropathy, the foot process effacement was seen between 3 and 10 days following PAN injection. ③ The podocin expression began to decrease on day 1, and prominently decreased on day 3 and day 10 compared with those of the Control group (P< 0.01). On day 20, the podocin expression resembled that of day 1, remaining lower than that of the Control group (P< 0.05) although it partly retrieved with the decreased proteinuria. The podocin expression was negatively correlated with proteinuria (r= -0.786, P< 0.05). ④ Podocin staining showed a very fine linear-like pattern along the capillary loop in the Control group. It presented a discontinuous pattern on day 1, a granular pattern on day 3, more coarse granular on day 10 and gradually recovered to a linear-like pattern on day 20. ⑤ Podocin mRNA expression levels were slightly elevated on days 1, 3 and 10 ( 1.2, 1.5, 1.4 folds as the Control group respectively) and recovered to a normal level on day 20 compared with those of the Control group. Conclusions Podocin may be involved in the development of proteinuria and it may be a useful early marker of podocyte injury in nephropathy.