摘要
目的 :探讨裂孔隔膜分子nephrin、podocin和足细胞骨架蛋白α actinin及足突形态变化与蛋白尿发生的关系。方法 :建立嘌呤霉素 (PAN)大鼠肾病模型 ,用体视学方法检测足突形态改变 ;用免疫荧光染色、图像分析和实时定量PCR方法动态观察PAN注射后不同时间点各分子蛋白及mRNA表达量及分布变化。结果 :蛋白尿出现前 ,PAN注射 2d时 ,足突肿胀、nephrin和podocin分布改变、podocin蛋白减低 ;5d时 ,上述改变进一步加重、nephrin蛋白及mRNA表达量下降。第 1 0天尿蛋白显著升高 [(1 30 .8± 30 .7)mg/d ,P =0 .0 2 ],足突弥漫融合、nephrin和 podocin分布明显异常、蛋白表达量显著减低、mRNA表达量回复至对照组水平。蛋白尿恢复时 ,足突形态学指标明显恢复、podocin蛋白水平回复至对照组水平、nephrin蛋白水平仍低于对照组、α actinin蛋白水平显著增加伴分布异常。nephrin和 podocin蛋白表达量与足突体积密度呈负相关 (rnephrin=- 0 .78,P =0 .0 0 0 1 ;rpodocin= - 0 .76 ,P =0 .0 0 0 1 )。结论 :足突肿胀、足细胞分子nephrin、podocin分布异常及 podocin蛋白表达量减低发生在蛋白尿发生前 ,提示nephrin和
Objective: To investigate the association between nephrin, podocin and α actinin of the glomerular podocyte molecules, the morphometric change of podocyte foot process and the development of proteinuria. Methods: Puromycin aminonucleoside (PAN) nephrosis was established. Immunofluorescence staining, image analysis and real time quantitative PCR were employed to study the distribution and quantitation of glomerular expression of nephrin, podocin and α actinin. Morphometric methods were applied to evaluate the morphology change of podocyte foot processes under electron microscopy. Results: (1) Before the onset of proteinuria, 2 days after PAN injection, the podocyte foot process became swollen;nephrin and podocin staining were changed into discontinuous pattern accompanied by the decrease of podocin staining intensity. The foot process became more swollen on day 5,and podocin intensity continued to decrease. Meanwhile, nephrin decreased significantly both in protein intensity and at mRNA level. (2) When heavy proteinuria [(130.8±30.7) mg/d, P =0.02]occurred, complete effacement of podocyte foot processes was revealed; both podocin and nephrin staining intensity decreased dramatically( P <0.01), and no linear staining could be observed; nephrin and podocin mRNA gained back. (3) During the recovery of proteinuria, the foot process morphology recovered stepwise; both the intensity of nephrin and podocin increased. When proteinuria disappeared, the podocyte foot process reappeared; podocin immunofluorescence intensity recovered whereas nephrin did not; the intensity of α actinin increased significantly and the distribution changed too. (4) Podocyte foot process volume density correlated negatively with nephrin( r nephrin =-0.78, P = 0.000 1) and podocin immunofluorescence intensity( r podocin =-0.76, P = 0.000 1), respectively. Conclusion: Before the onset of proteinuria, the first response of podocyte is the swollen foot process, the distribution change of nephrin and podocin and the de creased podocin intensity. There was close relationship between nephrin, podocin protein level anddistribution pattern with the development of proteinuria and podocyte foot process effacement, whereas no major role was found for mRNA of nephrin and podocin. Our results suggest that proteinuria might occur after series of events of nephrin and podocin distribution change, their protein and mRNA expression level decrease, and morphology change of podocyte foot process.
出处
《北京大学学报（医学版）》
CAS
CSCD
北大核心
2004年第2期139-144,共6页
Journal of Peking University:Health Sciences
基金
国家自然科学基金 ( 3 0 170 992 )资助
国家教育部留学回国人员科研启动基金 ( 2 0 0 3 14 )资助~~
