Role Of Heme Oxygenase-1 In Limb Ischemic Postconditioning Reducing Cerebral Ischemia Reperfusion Injury

Objective: To investigate the role of heme oxygenase-1(HO-1) in limb ischemic postconditioning(LPost C) reducing cerebral ischemia reperfusion injury. Methods: 80 male SD rats were randomly divided into sham-operation group(sham), ischemia reperfusion group(I/R), limb ischemia postconditioning group(LPost C) and inhibitor of HO-1 group(Zn PP), 20 rats of each group. The ischemia and reperfusion injury model was established by line embolism with paraffin to block the middle cerebral artery. It includes three cycles of 5min to occlusion and 5min to loosen the bilateral femoral artery to make the limb ischemia postconditioning model(LPost C). After 24 h reperfusion, adopted TTC to measure cerebral infarction volume. TUNEL was used to detected neuronal apoptosis. MDA content and SOD activity in brain tissue were measured by spectrophotometer. Immunohistochemistry and Western blot method were employed to detect the expression of HO-1. Results: The expression of HO-1 and SOD activity were lower whereas MDA content was higher in I/R group than in sham group(P<0.01). When compared with I/R group, the cerebral infarction volume diminished, and the number of nerve cell apoptosis significantly reduced, and the expression of HO-1 sharply increased, meanwhile SOD activity rose and MDA content decreased in LPost C group(P<0.01). Cerebral infarction volume, nerve cell apoptosis and MDA content stronger, whereas the expression of HO-1 and SOD activity markedly lower in Zn PP group than in LPost C group(P<0.01). Conclusions: Limb ischemia postconditioning play the role to protect cerebral ischemia reperfusion injury, and the mechanism may be related to the upregulation of HO-1.