The role of renal cortical blood flow in the development of proteinuria

doi:10.3969/j.issn.1001-9448.2000.12.003

Abstract：Objective To study the role of renal cortical blood flow (RCBF) in development of proteinuria in rat. Methods ① Neophrotic syndrome was induced by single injection of adriamycin in rat; ② Urinary protein excretion was quantitated every 24 hours; ③ Rat blood pressure was measured by multi - function monitor and renal cortical blood flow was measured by multi - function monitor and renal cortical blood flow was neasured by laser - doppler specnoscopy respectively on day 4, 8, 32 and 56 after adriamycin injection; ④ Endothelin (ET) and nitric oxide (NO) in rat plasma and renal cortical homogenate were measured by radioimmunoassay and by Griess' s method; ⑤The correlation between RCBF and urinary protein, ET or NO was compared respectively. Results ①Urinary protein was normal 4 days after adriamycin injection, increased on day 8; peaked on day 32 and decrease on day 56; ②The arterial blood pressure of the 4 time points was 118, 119, 118 and 117 mmHg in normal rat and was 116, 124, 129 and 121 mmHg in nephrotic rat. There was no difference between nephrotic and normal rat (P<0.05) ;③RCBF of the 4 time points was 66,68,67 and 70 in control and was 58, 52,19 and 23 in nephrotic rat, with significant difference between the two group at all time point; ④ET of the 4 time points in nephrotic rat was 134, 150,538 and 445 ng/ml, with significant increase on day 32 and 56 compared to control (P<0.05). The renal cortical ET of the 4 time points were 365, 653, 1 527 and 1 394, significantly higher than that of corresponding time points in control (P<0.05); ⑤Plasma NO in nephrotic rat was 40, 36, 8 and 11 nmol/ml, significantly lower than that of control from day 32 to day 56. The NO of renal cortex was significantly lower than that of normal rat (P<0.05) .There was no correlation between artery blood pressure and RCBF or urinary protein. Conclusion RCBF has more important role in the development of proteinuria than artery blood pressure. The changes of RCBF may be due to increased renal cortical ET and decreased NO.