蛋白尿慢性肾纤维化大鼠肾组织Nephrin蛋白表达动态变化

目的检测蛋白尿多柔比星肾损伤大鼠足细胞相对数目及Nephrin的表达变化,探讨Nephrin表达变化在蛋白尿发生发展中的意义。方法 36只雄性SD大鼠随机分为对照组(n=16)和模型组(n=20),应用多柔比星(4 mg/kg)尾静脉注射、一周末后重复的方法建立大鼠蛋白尿慢性肾纤维化模型,于第1次注射多柔比星后4、7、10、13周末收集标本,观察大鼠24 h尿蛋白、血生化指标等,光镜、电镜观察肾组织的病理改变,Western blot检测大鼠肾皮质中Nephrin蛋白的表达,免疫组化观察Wilm肿瘤蛋白1(WT1)表达。结果①第4周末开始,模型组大鼠蛋白尿显著高于对照组(P<0.01)。②肾脏病理在第7周末时出现局灶肾小球硬化,第13周末肾小球呈明显硬化表现,第10周末见足细胞脱离基底膜。③肾皮质WTl蛋白的表达量逐渐减少,但肾脏Nephrin蛋白表达4周末时较对照组增加(P<0.01),7周末后逐渐降低。结论足细胞相对密度及相对数量的减少可能是蛋白尿发生、发展的重要因素,病程中Nephrin蛋白表达量呈先升后降的变化趋势,疾病早期其表达增加可能是足细胞抵抗损伤的一种代偿反应。

Dynamic changes of Nephrin expression in rats with chronic proteinuria renal fibrosis

Objective To investigate the expression and significance of podocyte number and Nephrin expression in adriamycin nephritic rats.Methods 36 male SD rats were randomly divided into the normal control group(n=16) and model group(n=20) induced by intravenous injection of adriamycin 4 mg/kg,again after a week.Specimens were collected at the 4th,7th and 10th week.The blood and urinary biochemical indicators were detected,and the pathological changes of the renal tissues were observed under light microscope and electron microscope.The expression levels of WT1 and Nephrin in renal cortex were examined by Western blot.Results Compared with the control group,24 h urine protein excretion,ALB,TG and TC in pathologic model rats gradually increased(P< 0.01) in model group.At the 7th week,light microscope and electron microscope showed obvious glomeruli hypertrophy,focal fibrosis in tubulointerstitium and glomerulus in model group rats.The expression of WT1 decreased gradually in model group(P<0.01).The expression of Nephin protein increased significantly at 4th week(P<0.01),but gradually declined from 7th week.Conclusion A relative decrease of the density in the number of podocytes might be the significant factor that results in considerable proteinuria occurence and development.Nephrin level initially increased but gradually declines.The enhanced expression might be a compensatory reaction of podocyte to injury in early stage of the disease.