Ischemic preconditioning modifies mortality and inflammatory response

PURPOSE: To evaluate the effect of ischemic preconditioning on mortality, inflammatory mediators and oxidative stress after intestinal ischemia and reperfusion. METHODS: Male Wistar rats were allocated according to the period of ischemia with or without ischemic preconditioning which consist on clamping the superior mesenteric artery for 10 minutes followed by reperfusion for 10 minutes before the sustained ischemia period. Mortality was assessed in Phase 1 study, and the CINC-1, CINC-2 and MDA levels in the lungs were analyzed in Phase 2. RESULTS: Mortality was lower in the ischemic preconditioning group subjected to 90 minutes of ischemia compared to the group without ischemic preconditioning (I-90: 50% and IPC-90: 15%, p=0.018), and it was lower in the ischemic preconditioning group as a whole compared to the groups without ischemic preconditioning (IPC-14% and I=30%, p=0.006). Lower levels of MDA, CINC-1, and CINC-2 were observed in the animals that were subjected to ischemic preconditioning compared to the animals that were not (MDA: I-45=1.23 nmol/mg protein, and IPC-45=0.62 nmol/mg protein, p=0.0333; CINC-1: I-45=0.82 ng/mL and IPC-45=0.67 ng/mL, p=0.041; CINC-2: I-45=0.52 ng/mL and IPC-45=0.35 ng/mL, p=0.032). CONCLUSION: Ischemic preconditioning reduces mortality, inflammatory process and oxidative stress in rats subjected to intestinal ischemia and reperfusion.

Effect of alpha-tocopherol pretreatment on infarct size following 90 minutes of ischemia and 4 hours of reperfusion in dogs.

The present study was designed to evaluate the effects of pretreatment with antioxidants on free radical mediated reprefusion injury. Five dogs were fed with alpha-tocopherol (1000 IU/kg, bw) for ten days prior to 90 min of left anterior descending coronary artery occlusion followed by 4 hours of reperfusion. Infarct size, serum and myocardial lipid peroxidation were measured in pretreated and in untreated animals. Infarct size, as percentage of myocardial tissue at risk in alpha-tocopherol pretreated animals was 5.86+/-0.83 and was 39.35+/-7.58 in the untreated animals. Following reprefusion in untreated group, the values of serum and myocardial tissue lipid peroxidation were significantly higher than observed values in alpha-tocopherol treated animals. alpha-tocopherol pretreatment significantly reduced the myocardial infarct size and percent necrosis in the left ventricular mass in comparison to the untreated animals. These results suggest that alpha-tocopherol pretreatment possibly helps in reducing infarct size.