阿霉素肾硬化大鼠肾小球细胞增殖和p27蛋白表达的研究

Glomerular cell Proliferation and p27 Expression in Experimental Glomerulosclerosis

目的 :研究肾硬化大鼠中细胞周期负调控蛋白 p2 7的表达和肾小球细胞增殖的关系 ,以探讨肾硬化发展过程中肾小球细胞增殖的分子机制。方法 :3月龄雄性Wistar大鼠随机分为对照组 (18只 )和实验组 (2 2只 )。在实验第 4周、8周和 12周测定血尿素氮 (BUN)、血肌酐 (Scr)和 2 4h尿蛋白定量 (TP/2 4h)并于第 12周测定大鼠平均动脉压 (MAP)。用半定量RT -PCR方法检测肾小球中PCNAmRNA的表达 ,同时采取免疫组织化学方法检测肾小球内增殖细胞核抗原 (PCNA)和细胞周期负调控蛋白 p2 7的表达。 结果 :BUN、Scr和TP/2 4h在各时间点均较同期对照组明显升高 (P <0 .0 5或P <0 .0 1)。实验组大鼠平均动脉压显著升高 (P <0 .0 1)且肾脏组织病理损害进行性发展。实验组各时间点PCNAmRNA表达明显增强 ,增殖指数进行性升高。对照组p2 7蛋白有一定水平表达 ,而实验组其表达进行性下降 ;p2 7蛋白表达与增殖指数和PCNAmRNA表达呈负相关。 结论 :肾硬化大鼠中肾小球细胞增殖随病变的进展而进行性增加 ,细胞周期调控蛋白 p2 7可能参与了肾硬化中肾小球细胞增殖的调控。

Objective:To study the glomerular cell proliferation and p27 expression in rat glomerulosclerosis.Methods:Adult male Wistar rats were randomly assigned to control and experimental group.Blood urea nitrogen(BUN),serum creatinine(Scr) and 24 hour urine protein excretion(TP/24 h)were measured at 4,8 and 12 weeks.The mean arterial pressure(MAP)and the average areas(A G) and volumes(V G) of glomeruli were determined.Proliferating cell nuclear antigen(PCNA) was determined by semi-quantitative RT-PCR assay and the glomerular cell PCNA and p27 protein expression was evaluated by immunohistochemistry.Results:BUN,Scr,TP/24 h and MAP in experimental rats increased progressively,and were significantly higher than that of control rats.Semi-quantitative RT-PCR revealed increased PCNA mRNA expression in the experimental glomeruli,which coincided with the results of proliferation indices.p27 decreased progressively and there was significan negative correlation between p27 and PCNA expression( r =0.8043, P <0.05).Conclusion:Glomerular cell proliferation increased progressively with the development of glomerulosclerosis.Decreased p27 expression is likely to participate in the regulation of glomeular cell proliferation.