Dynamic Changes of Adriamycin-induced Nephropathy Rats Model and Change of Podocyte Number and Nephrin Expression in Model

【Objective】 To investigate the expression and significance of the podocyte number and nephrin in adriamycininduced nephropathy rats. 【Methods】 Sixty-four Sprague-Dawley rats were divided into two groups: the model group (n = 40) and the control group (n = 24). The rats in the model group were injected with adriamycin via tail-vein twice every two weeks, while the rats in the control group were injected with saline in equal amounts at the same time. The blood and urinary biochemical indicators were detected at week 1, 4, 8, and 12 while the pathological changes of the renal tissues were observed under light microscope and electron microscope. The expression levels of nephrin and the podocyte number were examined by immunohistochemistry. 【Results】 ①Based on the pathological change of the renal tissues, the model was divided into two stage: the acute stage (week 1-4 ) and the chronic stage (week 5-12). In the end of the fourth week, swollen podocytes were observed. In the end of the eighth week, adhesion between glomeruli and Bowman's capsule were observed. In the end of the twelfth week, some mild or midrange glomeruli sclerosis were observed; ②Nephrin presented a weak signal in the end of the first week (P 0.05) and the podocyte number started to decrease (was about 84 % compared with control group) at the end of the eighth week (P 0.05); ③Expression of nephrin and podocyte number were negatively correlated with the 24 h urinary protein, blood urea nitrogen and serum creatinine. Podocyte number was positively correlated with nephrin. 【Conclusions】 ①The acute and chronic adriamycin nephrosis model was successfully established by injecting adriamycin 0.004 mg / g into tail-vein twice every two weeks. The acute model is similar to human minimal change disease and the chronic model is similar to human focal segmental glomerulosclerosis (FSGS); ② The decrease of nephrin expression and the change of its distribution modality might be the significant factors that result in considerable proteinuria; ③FSGS happens when the podocyte number decreased about 16%.