Resveratrol, a Component of Wine and Grapes, in the Prevention of Kidney Disease

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Abstract
Ischemia is an inciting factor in 50% of incidences of acute renal failure, and it increases the risk of organ rejection after renal transplantation. We have previously demonstrated that resveratrol (RSV) reduces ischemia‐reperfusion (I/R) injury of rat kidney both by antioxidant and anti‐inflammatory mechanisms. However, a clear morphological demonstration of this activity has not been made. To answer this question we have performed a new set of experiments following the experimental protocol reported below to investigate the effects of I/R injury and RSV pretreatment on kidney morphology by computerized morphometric analysis. Both renal arteries were clamped for 40 minutes in 40 male Wistar rats (b.w. 220 ± 20 g); 20 rats were pretreated with RSV 1 μM e.v. 40 minutes before clamping. All animals were reperfused for 24 hours and then sacrificed. Histological examination showed tissue conservation in treated rats. I/R‐induced glomerular collapse (as revealed by mean glomerular volume and glomerular shape factor) was significantly reduced by RSV pretreatment. Capillary tuft/Bowman's capsule area ratio was enhanced in the I/R group suggesting tubular hypertension. RSV pre‐treatments significantly reduced this parameter to the control value. The number of platelet clots in the capillary tuft and tubular necrosis were also reduced by RSV versus I/R group. l‐NAME administration worsened both functional and structural damage. Finally, cGMP urinary levels were markedly reduced from 12.1 ± 8.4 nmol/day to 0.10 ± 0.10 nmol/day in the I/R group. RSV provided cGMP (5.01 ± 1.5 nmol/day, P < 0.05). As expected, l‐NAME administration significantly reduced cGMP in urine (0.71 ± 0.6 nmol/day). The present study confirms the protective effect of RSV pretreatment in I/R injury of rat kidney and suggests multiple mechanisms of action.