Oxidative stress in a rat model of nephrosis can be quantified by electron spin resonance

Abstract

The pathogenesis of nephrotic syndrome is not clear. In this study, we used electron spin resonance (ESR) to evaluate levels of reactive oxygen species in rats with puromycin aminonucleoside (PAN)-induced nephrosis. Twenty-six Wistar rats were divided into four groups: (1) PAN treated, (2) PAN treated and alpha-tocopherol supplemented, (3) supplemented with alpha-tocopherol only, (4) control. On day 9, urinary protein excretion was measured. On day 10, all animals were sacrificed with retrograde perfusion via the aorta to obtain renal venous perfusates. The signal intensities of ascorbate radicals in the perfusates were determined by ESR. After perfusion, the kidneys were isolated and sieved to obtain glomeruli for determination of glomerular thiobarbituric acid-reactive substance (TBArs) and alpha-tocopherol. Urinary protein excretion by PAN-treated rats increased significantly on day 9 and was reduced by alpha-tocopherol supplementation. The ascorbate radical intensity and glomerular TBArs level were higher in PAN-treated than in control rats and were both suppressed to control levels by alpha-tocopherol supplementation. There were positive correlations between ascorbate radical intensity and the daily urinary protein, as well as between ascorbate radical intensity and the glomerular TBArs level. Hence, it is possible to quantify oxidative stress due to PAN nephrosis by ESR. Our findings suggest that lipid peroxidation plays an important role in the pathogenesis of proteinuria in PAN-treated rats.

Permeability, Ultrastructural Changes, and Distribution of Novel Proteins in the Glomerular Barrier in Early Puromycin Aminonucleoside Nephrosis

“…The pathogeneses of both MCNS and PAN are unclear. PAN has been shown to involve reactive oxygen species and/or DNA damage leading to cell cycle arrest [45,46]. Zhu et al[47] describe a decreased tyrosine phosphorylation of nephrin in PAN, leading to less interaction with phosphoinositide 3-kinase and finally decreased phosphorylation of the anti-apoptotic molecule Akt.…”

Chromosomes 18 and X are quantitative trait loci for nephrotic-range proteinuria in rats

“…At the time of this analysis, PhysGen has bred adult consomic strains subjected to the "Renal B" protocol for rat chromosomes 1, 2, 4, 6,7, 9, 11,13, 16,18, and 20, and for the rat Y chromosome. For chromosomes 2,4,6,7,9,11,13,16,18,20, and Y, consomic strains consisted of the specific Brown-Norway (BN) rat chromosome introgressed within a Dahl salt-sensitive (SS) rat background. The chromosome 1 consomic strain consisted of BN chromosome 1 within a fawn-hooded hypertensive (FHH) rat background.…”

“…We stratified protocol analyses by gender, allowing for analysis of X-chromosome effects as well. Therefore, our analysis included consomic or congenic strains covering 15 of the 22 rat chromosomes (1,2,4,6,7,8,9,11,12,13,16,18,20, X, and Y). Although the PhysGen database includes animals subjected to hypoxia, only those rats in the normoxic group were included in our analysis in order to avoid confounding molecular effects due to hypoxia.…”

“…Therefore, all phenotype measurements except serum creatinine were assessed via our a priori filter criteria, across all available consomic strains and stratified by gender. As a reference point for defining nephrotic-range proteinuria in rats, puromycin aminonucleoside-induced nephrosis in rats manifests nephrotic-range proteinuria at a urine excretion rate of greater than approximately 150 mg/day [13].…”

mTOR inhibition with temsirolimus causes acute increases in glomerular permeability, but inhibits the dynamic permeability actions of puromycin aminonucleoside

“…The PAN model has over the years become an experimental prototype of human minimal change disease and focal segmental glomerulosclerosis (39), and there is accumulating evidence that ROS generation and oxidative stress are main features of the pathogenesis of the glomerular barrier disruption induced by PAN (13,20,36,42,43,50). Hence, an increased production of ROS will activate TRPC6 Ca 2ϩ channels and intracellular Ca 2ϩ signaling (50) to increase glomerular permeability and to eventually produce DNA damage, cell cycle arrest, and thereby cell injury (32).…”