Expression and Significance of Nephrin and CD2AP in Adriamycin-induced Nephrotic Rats

【Objectives】 To dynamically observe the role of nephrin and CD2-associated protein (CD2AP) in adriamycin-induced nephrotic rats, and to explore the possible effects on the occurrence and development of proteinuria. 【Methods】 Seventy-two rats were divided into two groups: model group (n = 36) and control group (n = 36). The rats in model group were injected with adriamycin (6 mg / kg) via tail-vein for one time, while the rats in control group were injected with saline. At day 3, 5, 7, 14, 28, and 42, the kidney tissues of six rats were studied after adriamycin injection using electronic microscope, real time PCR, and immunohistochemistry. 【Results】 ① Nephrin mRNA expression at day 7, nephrin protein expression at day 14, and CD2AP (mRNA and protein) expression at day 28 increased in the rats in model group, respectively. ② Compared with the control group, the distribution of nephrin and CD2AP shifted from a linear-like pattern along the capillary loops of glomerulus to a discontinuous coarse granular or sheet-like distribution. ③ The mRNA expression of nephrin and CD2AP were positively correlated with the amount of 24 h urinary protein (r = 0.878, P 0.01; r = 0.945, P 0.01). 【Conclusions】 ① Nephrin presents early over-expression and abnormal distribution, suggesting possibly a cause of proteinuria occurrence and an important early indicator for acute podocyte injury. ② CD2AP exhibits lately over-expression, suggesting possibly a compensatory response against podocyte injury.