Expression of Hypoxia-Inducible Factor in the Cerebral Ischemia/Reperfusion Injury

We observe the expression of HIF-1 after middle cerebral artery occlusion (MCAO) by immunohistochemical method.Thirty-six Sprague-Dawley healthy male rats, with body mass of 250-330 g, were used in this study. Thirty-six rats were randomized into 3 groups: pre-ischemia group, sham-operation group and control group, with 12 rats in each.Rats in the pre-ischemia group were created into pre-ischemia models by two embolisms twice. Three days after ischemic preconditioning, middle cerebral artery (MCA) was occluded for 2 hours with the same method. After being perfused for 22 hours, the rats were euthanized. In the sham-operation group, rats were not given the treatment of pre-ischemia. In the first operation, only common carotid artery (CCA) and its crotch were exposed in the first operation, and MCA was not blocked by inserting embolism. At postoperative 3 days, rats were euthanized after being subjected to MCAO for 2 hours and reperfusion 22 hours by the same procedure as that in the pre-ischemia group. As for each rat in the control group, only CCA and its crotch were exposed, and no any other treatment was carried out on them.Brain tissue of each rat was performed immunohisto- chemical staining at reperfusion 22 hours after pre-ischemia, HIF-1 expression and brain infarct volume were detected. Thirty-six Sprague-Dawley rats were involved in the experiment. During the experiment, 8 rats dropped out, and another 8 rats were supplemented. The infarct volume of rats in the pre-ischemia group was significantly smaller than that in the sham-operation group (P <; 0.01). HIF-1 expression was not found in the control group, but many HIF-1 positive cells were found in the other two groups. Absorbance in the pre-ischemia group was significantly higher than that in the sham-operation group (P <; 0.01). Slight ischemia caused preconditioning can increase HIF-1 content, and it is one of protective mechanisms for nerve cells.