Podocin在大鼠微小病变肾病模型中的表达和分布

Expression and distribution of podocin in rats model of minimal change disease

目的 :观察podocin在大鼠氨基核苷嘌呤霉素 (PAN)肾病模型中的表达和分布 ,探讨其在蛋白尿发生中的可能作用。 方法 :建立大鼠PAN肾病模型 ,应用光镜、电镜观察肾脏病理改变 ,免疫荧光染色图像分析以及半定量RT PCR的方法 ,分别检测不同时间点 (1、3、1 0、2 0天 )大鼠肾组织中podocin的表达。 结果 :①PAN注射后第 1、3、1 0、2 0天大鼠肾小球podocin的表达强度分别为 :4 5 0 3± 5 1 0、33 35± 6 4 1、1 3 5 8± 3 73、4 2 34± 6 6 5 ,显著低于正常对照组 (5 4 95± 6 2 5 ,P <0 0 1 ) ,其中第 1 0天的表达强度最低。podocin的表达与尿蛋白排泄量呈负相关 (r=- 0 786 ,P <0 0 1 ) ;②podocin在正常大鼠肾小球沿毛细血管袢呈均匀连续的线样分布 ;模型第 1天podocin在肾小球局部呈颗粒状分布 ;第 3天呈弥散性的颗粒状分布 ;第 1 0天呈粗大的颗粒状分布 ;第 2 0天podocin的分布逐渐恢复为线样 ;③PAN注射后第 1、3、1 0、2 0天大鼠肾小球podocinmRNA的表达分别为正常对照组的 1 2、1 5和 1 4倍 ,第 2 0天大鼠肾小球podocinmRNA水平恢复正常。 结论

Objective:Podocin is new protein,which was first found in the steroid resistant family nephrotic syndrome.The aim of this study is to investigate the expression and distribution of podocin in development of proteinuria in rats with puromycin aminonucleoside (PAN) nephropathy Methodology:Thirty male SD rats,weight from 80 to 100g,were enrolled in this study.They were randomly divided into the nephropathy model and normal control group groups.The nephropathy model was established by a single intraperitoneal injection of PAN 15 mg/100g.The rats with nephropathy were sacrificed at day 1,3,10 and 20 after PAN injection.The renal histology was observed by light microscope,electronic microscope.The indirect immunofluorescence staining and semiquantitative reverse transcription PCR were used to detect the expression of podocin. Results:①In rats with PAN nephropathy,the intensity of podocin staining began to decrease to day 1(45 03±5 10),and prominently decreased at day 3(33 35±6 41) and day 10(13 58±3 73) compared with that in normal control group (54 95±6 25, P <0 01) At day 20,the staining intensity(42 34±6 65) was still less than that in normal control group ( P <0 01) although it partly retrieved with the decreased proteinuria.The staining intensity of podocin was negatively correlated with the amount of proteinuria( r = -0 786 , P <0 01).② Glomerular podocin staining showed a very fine linear like pattern along capillary loop in normal control group.It shifted a discontinuous pattern at day 1,a granular pattern at day 3,more coarse granular at day 10 and gradually recovered to linear like pattern.③ The mRNA expression of podocin slightly elevated at days 1、3 and 10(1 2,1 5,1 4 fold respectively, P <0 01) and recovered to normal level at day 20 ( P =0 11) compared with that in normal control group. Conclusion:The decreased expression of podocin and its abnormal distribution were closely associatied with the development of proteinuria in PAN nephropathy.