Podocin在多柔比星肾病大鼠模型中的表达及意义

Significance and Expression of Podocin in Adriamycin-Induced Nephrotic Rats

目的建立多柔比星肾病(ADN)大鼠模型,观察足细胞相关分子podocin在模型不同病理时期mRNA的表达,探讨podocin分子在肾病发生发展过程中的作用。方法雄性SD大鼠48只[体质量(230±20)g,月龄2～3个月],随机分为模型组和对照组,每组24只。模型组鼠尾静脉注射多柔比星6.5mg/kg,建立ADN模型。对照组注射9g/L盐水。分别于第2、4、6、8周每组各处死大鼠6只。处死前1天收集24h尿液,检测24h尿蛋白,应用光镜和电镜观察各组肾组织病理改变,Trizol法提取肾皮质总RNA,采用实时荧光定量反转录PCR检测其各时间点肾组织podocin mRNA表达。结果模型组大鼠实验第2、4、6、8周均表现为大量蛋白尿,各时间点24h尿蛋白较对照组均明显升高(Pa<0.01),模型组大鼠肾组织病理在肾病早期表现为微小病变型,随着病情进展,第6-8周呈现局灶性节段性肾小球硬化病理表现;电镜下可见模型组随着病变进展,足细胞损伤进行性加重。在病变早期可见足突增宽、融合,晚期足突消失,核固缩等表现。模型组第2周肾组织podocin分子mRNA表达明显升高(P<0.01),第4周时下降,第6-8周进一步下降(Pa<0.05)。结论Podocin分子在肾病综合征发生发展中起重要作用,podocin mRNA表达变化可能与肾病病理类型密切相关。

Objective To observe the expression of podocin in different pathological mechanism of adriamycin - induced nephrotic （ADN） rats,and investigate the role of podocin in occurrence and development of nephropathy. Methods Forty - eight SD rats [ weighted （ 230 ± 20） g, aged 2 - 3 months ] were divided into model group （ n = 24） and control group （ n = 24 ）. Adriamycin of 6.5 mg/kg was injected via the tail vein to create ADN model while the normal control group received 9 g/L sodium chloride with the same volume. The changes of the following indexes were observed in the 2^nd ,4^th ,6^th ,8^th weeks. Urine fluid of 24 hours was collected to detect the urine protein the day before the animal got sacrificed. The histopathologic change was detected by light microscope and electron microscope ,mRNA expression of podocin in cortex of kidney was detected by real time fluorescent quantitative RT - PCR. Results Massive proteinuria came out from model group in week 2,4,6,8. The amount of urine protein in model group increased significantly at the end of the 2^nd ,4^th ,6^th ,8^th week compared with control group. The model group developed from minimal change disease to focal segmental glomerulosclerosis in the 6^th to 8^th weeks observed by optical microscope. Podocyte uhralstructure was observed by electron microscope ：foot process conflurence in the early disease ,foot process effacement and chromatin raritas in the end. Podocin mRNA expression increased significantly in the 2^nd week in model group（ P 〈 0.01 ） and decreased in the 4^th week ,and were lower in the 6^th to 8^th weeks later in model group than that in control group（ Pa 〈 0.05 ）. Conclusion Podocin plays an important role during the pathological course of nephrotic syndrome and maybe have a close relationship between the change of podocin mRNA expression and pathology type of nephropathy.