Resveratrol, a component of wine and grapes, in the prevention of kidney disease

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 microM 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.