Combined use of ischemic preconditioning and postconditioning in the rat skin flap

Reperfusion injury by the abrupt restoration of circulation after the prolonged ischemia has been remained unsolved problem in the reconstructive microsurgery. We hypothesized that the combination of ischemic preconditioning and ischemic postconditioning would result in preservation of rat epigastric skin flap after ischemic period. We used 6x3 cm sized epigastric skin flap in 40 Wistar rats. Ischemic preconditioning was performed before ischemic period by 3 cycles of 10 minutes of repeated ischemia/reperfusion periods. A cycle of 15 seconds of full reperfusion, followed by 15 seconds of complete reocclusion was repeated six times (3 min of total intervention) after ischemic period and prior to the unlimited reperfusion. Global ischemia period was 6 hours in all flaps. The animals were allocated randomly into 4 groups, each group containing 10 animals. Group 1: Control group. Six hours of complete ischemia was induced by clamping the pedicle using a vascular clamp. Group 2: Ischemic preconditioning group. IP was performet prior six hours of complete ischemia. Group 3: Ischemic postconditioning group. After six hours of complete ischemia ischemic postconditioning was performed. Group 4: Ischemic preconditioning plus ischemic postconditioning group. Prior six hours of ischemia preconditioning was performed. After that 6 hours ischemia was performed. Finally postconditioning was performed after final ischemia. Flap viability was assessed 1 week after the surgical procedure, and surviving flap area was recorded as a percentage to the whole flap area. Total 3 rats (group 1: 1rat died, group 2: 1 rat because of autocannibalization, and group 4: 1 rat because of autocannibalization) were exclude from this study. Preconditioned, postconditioned and preconditioned + postconditioned animals demonstrated a significantly lower area of flap necrosis than the control group. Statistical analyses revealed meaningful differences between groups 2 and 3. However, there was no statistical difference between groups 2 and 4 and groups 3 and 4. As a conclusion, ischemic preconditioning and postconditioning have protective effects on ischemia-reperfusion injury in the epigastric skin flap model. The combination of preconditioning and postconditioning offered no additional benefit over either intervention alone in the skin flap model