Relationship Between Expression Of Glomerular Slit Diaphragm Molecule And Oxidative Stress Reaction

Objective This study aimed to explore the cause of podocyte injury by analyzing the relationship between slit diaphragm protein injury and oxidative stress reaction.Methods(1) Nephrosis was induced by single intravenous injection of ADR(5mg/kg) with or without treatment of prednisone or vitamin E.Control rats were intravenously injected with normal saline.The renal cortex and urine were taken to detect oxidative stress reaction indexes and proteinuria and the protein expression of nephrin,then the relationship between them was evaluated.(2) To observe the changes of 24h-urinary protein excretion,oxidative stress reaction indexes and glomerular slit diaphragm protein expression treated with ADR and vitmin E or ADR and prednisone.(3) To collect peripheral blood or urinary samples in the morning of children with nephrotic syndrome(NS).The level of serum malondialdehyde(MDA),superoxide dismutase(SOD) and total antioxidative capacity(T-AOC) were measured by chemical chromatometry.And urinary PCX content was quantified by enzyme-linked immunosorbent assay(ELISA).Results(1) The levels MDA were increased,the renal activities of SOD and T-AOC were decreased in rats treated with ADR alone from day 7 till day 28 as compared with those in the control rats(P＜0.05).While 24h-urinary protein excretion by ADR-induced rats had been starting to increase obviously at day 14 and the increment persisted up to day 28(P＜0.01).Nephrin staining were a sable linear-like pattern along the capillary loops of glomerulus obtained from control rats.In ADR-induced rats,a light tan,discontinuous,short linear-like or punctiform staining pattern of nephrin was revealed from day 7 to day 28.The staining patterns of nephrin decreased in ADR-induced rats compared with control rats(P＜0.05).There were significant negative correlations between nephrin expression and MDA levels and 24h-urinary protein excretion(r =-0.732 and -0.894,respectively,P=0.000),and significant positive correlations between nephrin expression and SOD and T-AOC activities in renal cortex(r=0.822 and 0.869,respectively,P=0.000).(2) With intervention of vitamin E,renal MDA levels decreased and activities of SOD and T-AOC increased compared with ADR-induced rats at day 28(P＜0.05).The changes in molecule expression of nephrin,podocin,α-actinin-4 as well as 24h-urinary protein excretion were amendmented after treating with vitamin E or prednisone compared with ADR-induced rats(P＜0.05).(3) Active-stage NS had significantly higher serum MDA levels and lower serum SOD and T-AOC activities compared with the control groups(P＜0.05).(4) The level of Podocalyxin(PCX) content was significantly higher in the urine from patients with any case of NS compared with the control group(P＜0.05).The level of urinary PCX content was higher in the acute phrase of NS than in the catabasis(P＜0.05).There was obviously positive correlation between urinary PCX content and 24h urine protein excretion in acute phrase of NS(r=0.785,P=0.01).Conclusion(1) There existing increased peroxidatic reaction and decreased antioxygen capability in nephropathy condition.(2) There was evident relationship between mass proteuria and podocyte damage. Glomerular nephrin protein injury is closely related to oxidative stress reaction in ADR-induced rats.(3) Antioxidant and glucocorticoid play the protective effects on the renal injury of ADR- induced rats by ameliorating abnormal expression of slit diaphragm protein.