Abstract:
PURPOSE: Ischemia-reperfusion injury is a major cause of morbidity and mortality in cardiovascular surgery. The aim of this study was to evaluate the protective effects of ischemic pre- and post conditioning and concomittant application of these two methods in a rat model of lower extremity ischemia-reperfusion (IR).
MATERIALS and METHODS: Male Wistar-Albino rats (n=40) were divided into five groups. Sham group (n=8) underwent laparotomy but no ischemia. The infrarenal aorta was cross-clamped for 120 min. followed by 60 min. reperfusion in control (IR) (n=8) group. In ischemic post conditioning group (n=8) a period of ischemia for 5 min. followed by reperfusion for 5 min.repeated three times was formed at the beggining of repefusion. Three cycles of 10 min. of ischemia followed by 10 min of reperfusion was formed before IR in the ischemic preconditioning (n=8) group. In an other group synchronous application of pre- and post conditioning (n=8) was achieved. At the end of the reperfusion period, biopsy of the left gastrocnemius muscle was performed for determination of tissue malondialdehyte (MDA) and nitric oxide (NO) levels and blood samples were withdrawn for analysing serum cytokine (TNF-α, IL 1-β, IL-6) levels.
RESULTS: Tissue MDA levels were observed to be lower as compared with the control group and it was significantly reduced in the post-conditioning group. TNF-α level was lowest in the post-conditioning group. Interleukin 1-β was found to be significantly lower in all groups as compared with the control group. In the preconditioning and synchronous pre- and postconditioning groups MDA levels were lower than the level in control group.
CONCLUSION: Although the results were not statistically significant it was observed that there was a tendency towards reduced tissue injury in models of ischemic conditioning. These findings suugested that further studies are needed in order to clarify the effects of ischemic conditioning.
