Investigation effects of pheniramine maleate, peripheral hypothermia and peripheral hyperthermia to reducing ischemia reperfusion injury of extremity

Background: Ischemia-reperfusion (IR) injury is the tissue damage which caused by reperfusion of an ischemic tissue. Reperfusion triggers a cascade of acute inflammatory events which leading to cellular death and tissue dysfunction and necrosis. IR is commonly caused by tourniquet, amputation and replantation in orthopedic surgery. In this study, we aimed to investigate the protective effects of pheniramine maleate (Ph) and periferic hypothermia in rats which had been created experimentally ischemia reperfusion injury and compare the results with n-acetyl cysteine (NAC) known as an effective molecule for reducing IR. Materials and methods: Forty two Sprague-Dawley rats were seperated into 6 groups randomly (sham, IR, IR+local hypothermia, IR+local hyperthermia, IR+Ph, IR+NAC; n:7). To create ischemia we clamped the right femoral artery and applied tourniquet to the right hind limbs of rats during the 3 hours under general anesthesia. At the beginning of reperfusion, administered systemic Ph to the rats in the IR+Ph group and administered NAC to the rats in the IR+ NAC group. During two hours, the right hind limbs of rats in the IR+local hypothermia group were cooled by using cold water tank. And the right hind limbs of rats in the IR+local hyperthermia group heated similarly. At the end of the 24 hours reperfusion time, the right gastrocnemius muscles of all rats were sampled. In theese muscle samples; the oxidative parameters (Myleloperoxidase (MPO), supeoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS), poly adp ribose polymerase (PARP) levels) and inflammatory cells histopatologically were evaluated. The end of the one week reperfusion period, tibialis anterior muscles of all rats were sampled, then all of the rats were sacrificed. In these muscle samples, the iNOS staining and inflammatory cells histopathologically were evaluated. Results: In the IR group and IR+hyperthermia group, the levels of TBARS, PARP, SOD and CAT were found higher compared with those in the sham group. On the contrary, these oxidative parameters were found lower in IR+H, IR+Ph and IR+NAC groups compared with IR and IR+hyperthermia groups. Compared with the sham group; mononuclear inflammatory cells, tissue iNOS score and intensity staining in the IR, IR+hyperthermia groups were established increased. On the other hand, the histopathological parameters were found decreased in IR+H, IR+Ph, IR+NAC groups compared with the IR, IR+hyperthermia groups. Conclusion: In this study, we showed that NAC and Ph reduce the IR in muscle clearly, also hypothermia was more effective than NAC and Ph in reducing IR in muscle. Hyperthermia was found not effective in reducing or increasing IR. If our results are confirmed with new studies, NAC, Ph and hypothermia can be used for preventing or management of IR in clinical practises.