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目的探讨新生小鼠中足细胞损伤对肾小球发育的影响及其机制。方法于新生ICR小鼠出生后1 d注射嘌呤霉素(puromycin aminonucleoside,PA),并以注射生理盐水作为对照。观察出生后第2、4、8、12、30、60、90天时肾重/体重、尿蛋白、血压及组织学的改变。应用免疫组化及定量RT-PCR方法测定肾皮质内肾母细胞瘤基因(WT-1)、CD31、血管内皮生长因子(VEGF)及其受体Flk-1、血管生成素(angiopoietin,Ang-1、Ang-2)及其受体Tie-1、Tie-2的表达水平。结果注射PA后,新生小鼠肾重、体重均明显低于对照组。出生后第2天(注射PA后1 d)时,肾小球足细胞出现足突广泛融合和微绒毛的脱落；第12天时,肾小球内CD31的表达明显下降,部分肾小球萎缩、发育不良,肾皮质浅层小球成熟指数明显下降；第30天时,原先发育不良的肾小球逐渐被吸收；第60天时,剩余肾小球出现系膜区的扩张和小球节段性硬化。PA鼠在第30天时出现蛋白尿：第60天时血压显著增高。定量RT-PCR显示,第2天时肾皮质Ang-1表达明显上调,Flk-1及Tie-2明显下降。结论PA可以在早期损伤的新生ICR小鼠足细胞,改变VEGF、血管生成素系统的表达,导致肾小球毛细血管袢发育不良及在后期产生蛋白尿、高血压和肾小球硬化。
Objective To investigate the effect and mechanism of podocyte injury on glomerular development in newborn mice. Methods The neonatal ICR mice were injected with puromycin aminonucleoside (PA) 1 d after birth and injected with normal saline as a control. The changes of kidney weight / body weight, urine protein, blood pressure and histology were observed on the 2nd, 4th, 4th, 8th, 20th, 30th, 60th and 90th day after birth. Immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the expressions of nephroblastoma gene WT-1, CD31, VEGF and its receptor Flk-1, angiopoietin (Ang- 1, Ang-2) and its receptor Tie-1, Tie-2. Results After injection of PA, the newborn mice kidney weight and body weight were significantly lower than the control group. On the second day after birth (one day after the injection of PA), glomerular podocytes appeared extensive fusion of foot processes and shedding of microvilli. On the 12th day, the expression of CD31 in the glomeruli was significantly decreased, part of the glomerular atrophy, Dysplasia, renal cortical shallow ball maturation index decreased significantly; the first 30 days, the original dysplastic glomeruli gradually absorbed; the first 60 days, the remaining glomerular mesangial area expansion and segmental segmental sclerosis . PA rats developed proteinuria on the 30th day: blood pressure increased significantly on the 60th day. Quantitative RT-PCR showed that on the second day, the expression of Ang-1 in renal cortex was significantly up-regulated, and the expressions of Flk-1 and Tie-2 were significantly decreased. Conclusion PA can damage the podocytes of neonatal ICR mice, alter the expression of VEGF and angiopoietin, resulting in dysplastic glomerular capillary loops and proteinuria, hypertension and glomerulosclerosis in the later stage.