p38MAPK (p38) inhibition prevents ischemia/reperfusion-induced apoptosis of tubular cells. Rats were pretreated with the carrier DMSO or BIRB796 (B-796) (5 mg/kg BW) for 1 hour and subjected to 1 hour of renal ischemia followed by different time points of reperfusion (15 min, 2 days, 7 days). Kidneys were harvested at given time points of reperfusion and total tissue lysates were used to determine activation of caspase-3. A representative immunoblot is shown (A). IR-induced tubular cell death was assessed by TdT-mediated dUTP nick end labeling (TUNEL) staining at day 2 of reperfusion as described in Material and Methods. Representative images of the three regions of the kidney (cortex, corticomedullary junction and medulla) at 400x magnification and summary graph of the TUNEL positive cells are shown (B-C). Arrows point to the apoptotic cells with condensed nuclear material. Results are given as mean ± SEM (n = 4). *p < 0.05, ***p < 0.001 vs. vehicle-treated IR group.