Abstract
Background: Effectiveness of ischemic postconditioning to salvage tissues from ischemia-reperfusion damage has been shown in animal models but exact timing and duration of reperfusion/reocclusion cycles have not been studied in the literature. In this study we have evaluated the effects of short-interval postconditioning and tried to elucidate the most suitable reperfusion/reocclusion regime.
Methods: From forty rats 5 groups have been created. After dissection, the femoral artery has been clamped to produce ischemia which was maintained for 4 hours. Then, all extremities were reperfused. The first group was IR (ischemia + reperfusion) control group. In the other 4 study groups after ischemia postconditioning for 5 seconds (PC5), postconditioning for 10 seconds (PC10), postconditioning for 15 seconds (PC15), and postconditioning for 20 seconds (PC20) were applied. The animals were sacrificed, the gastrocnemius muscles were excised, and tissue analyses were utilized biochemically and macroscopically. Superoxide dismutase and nitric oxide (SOD and NO) level and muscle viability were evaluated.
Results: The muscle viability was found to be statistically increased in the postconditioning groups compared to the control group. In the postconditioning PC 15 group, NO, and muscle necrosis levels significantly decreased compared with the control group. In the PC10 and PC15 groups tissue NO levels were decreased but only between PC15 group and other groups this finding was statistically significant.
Conclusion: Reperfusion injury can be prevented by short-interval postconditioning and 15 seconds × 10 times reperfusion-reocclusion
cycles were found to be the most suitable approach.

Key words: Postconditioning, muscle, reperfusion injury, oxidative stress