Correlation Between The Expression Of Podocin MRNA And Oxidative Stress In Adriamycin-induced Nephrotic Rats

Objective To explore the possible association of oxidative stress reaction with the mRNA expression of podocin in adriamycin (ADR)- induced nephrotic rats.Methods ADR induced nephrotic rats models were established by a single injection of ADR 7.5mg/kg via the tail vein, while the control group received saline in equal volume at the same time. ADR rats were sacrificed at days 7,14 and 21 to collect urine and cortical kidney tissue. In situ hybridization(ISH)staining and semi-quantitative RT-PCR were employed to study the distribution and expression of podocin mRNA in kidney , the excretion quantity of proteinuria,the level of malondialdehyde (MDA), superoxide dismutase(SOD)and total antioxidative capacity (T-AOC) were measured ,then the relativity between the expression of mRNA podocin and oxidative stress was evaluated.Results(1)The excretion quantity of proteinuria increased significantly at day14(p<0.01)in ADR rats compared to the normal control, and persisted to day 21(P <0.01).(2)In ADR rats, The level of MDA was increased at day 7(P =0.02)and reached a significant level at day14 and day21(both P <0.01);the level of SOD decreased at day 14 (P =0.029)and persisted to day 21(P =0.001);No significant difference of the level of T-AOC was found between ADR rats and the control at day7 and day14,while at day21 decreased significantly (P =0.036).(3) The major site of podocin mRNA expression in kidney was found located in cytoplasm of glomerular cells. In experimental group, both the number and the intensity of positive cells increased notably as time progressed.(4) The semi-quantitative expression of podocin mRNA showed no obvious changes at day 7 ADR rats compared to control , while prominently increased at day14 and pesisted to day21 in ADR rats(both P <0.01).(5) There was positive correlativity between and the level of MDA ( r MDA=0.443,p<0.05);there was also significantly negative correlativity between the mRNA expression of podocin and SOD,T-AOC (rSOD =-0.703,p<0.01;rT-AOC =-0.467,p<0.01).Conclusion The mRNA expression of podocin is correlated with oxidative stress reaction in adriamycin-induced nephrotic rats.