Effect of hyperbaric oxygen preconditioning on the expression of HO-1 and ALK in cerebral ischemia-reperfusion rats

Objective To study the effects of hyperbaric oxygen (HBO) preconditioning on the expression of heme oxygenase-1 (HO-1)and anaplastic lymphoma kinase(ALK) in cerebral ischemia-reperfusion (IR) rats. Methods The Sprague-Dawley male rats were randomly divided into 3 groups: the middle cerebral artery occlusion (MCAO) and reperfusion group (n=8), the sham surgical group (n=7) and the HBO preconditioning + MCAO and reperfusion group (n=8). The HBO preconditioning rats were exposed to hyperbaric environment at a pressure of 0.2 MPa with 85% oxygen concentration, 1 hour a day, for a succession of 7 days. Modified Longa method was used to develop middle cerebral artery occlusion (MCAO) model and reperfusion was performed 2 hours after ischemia. Twenty-fours after termination of reperfusion, the samples were collected to perform TTC staining, and RT-PCR was used to detect the expression levels of HO-1 and ALK. Results HBO preconditioning could significantly reduce the scope of cerebral infarction(P<0.01). Additionally, the expression levels of HO-1 and ALK in the ischemia and reperfusion group were markedly increased, as compared with those of the sham surgical group, while the expression levels of HO-1 and ALK in the HBO group were considerably decreased, however, the expression level of HO-1 was obviously increased as compared with that of the sham surgical group (P<0.05). Conclusion HBO preconditioning could significantly decrease the down-regulation of HO-1 and ALK in the brain tissue of ischemia and reperfusion rats, which indicated that it might have a protective effect on the brain damage induced by ischemia and reperfusion. Key words: Hyperbaric oxygen preconditioning; Cerebral ischemia-reperfusion; Heme oxygenase-1; Anaplastic lymphoma kinase; Rat