Observe The Effects And Mechanism Of Hypoxic Postconditioning On Neuroprotection In Middle Cerebral Artery Occlusion -Reperfusion Rats.

BackgroundThe application of hypoxic preconditioning before ischemia can reduce ischemia-inducedbrain damage. Here, the ischemia tolerance occurs. However, the unpredictation of cerebralischemia limited the hypoxic preconditioning's application. Hypoxia post-processing began torise recently. After 7 days intermittent hypoxia in focal cerebral infarction model by electriccoagulation can significantly reduce the infarct volume. Because of difference between themodel with human, their conclusions need to be confirmed. Furthermore, the protection ofhypoxic postconditioning may caused by many mechanisms. In our experiment, male, SD ratswere subjected to middle cerebral artery occlusion–reperfusion models. We explored theprotection of hypoxic postconditioning by observing the dynamics state of HIF-1αin the brain,We hope our research can play a good role on clinical medicine.Objective:To Prepare a simple model of hypoxic postconditioning, and observe the effect of hypoxicpostconditioning on the expression of hypoxia-inducible factor-1α(HIF-1α) and mRNA in thebrain.Methods:36 male Sprague-Dawley rats were randomly divided into the hypoxia group and the controlgroup. In hypoxic group the mixed gas was entered slowly into a fixed volume container. Theflow rate of oxygen and nitrogen was adjusted, so that the oxygen concentration monitored byoxygen analyzer always remained at 12%. And then the rats were set in the container for 4 hoursper day. In control group the rats stayed in the same container in stead of air for 4 hours per day.The expression of HIF– 1αand mRNA was detected by immunohistochemistry and RT-PCRafter seven days.Results:The mean infarct volume of rats received hypoxia after 7 days' recovery was significantlyless than that of the comparable control group. Rats received hypoxia after 7 days' recovery showmild nerve lesions and less cell lysis; the expression of HIF-1αand mRNA in brain was significantly higher than that of the comparable control groupConclusion:Altogether, this study demonstrates for the first time that Rat MCAO / R 7 dayspost-treatment have a protective effect on the brain lesions, may be concerned with inducing theexpression of HIF-1α...