The Effects Of Adenosine Preconditioning On Expression Of HIF-1α、VEGF、EPO In Rat After Cerebral Ischemia Reperfusion Injury

BackgroundThe ischemic encephalopathy threat to human health seriously, it’ scharacteristics is high incidence and high morbidity and high mortality. It has brought pain and burden to the patients and families. So medical profession concern the ischemic encephalopathy consistently. Cerebral artery (MCA) blood incidence areas accounted for60%in ischemic cerebrovascular disease. Because of rats with low cost and homozygous good and cerebral vascular anatomy structure and function similar to humans,it has been become scholars produced the closest animal model of human cerebral infarction ideal experimental animals.ObjectiveTo adenosine preconditioning in rats of ischemia reperfusion,to observe the injury of brain tissue pathology structure and the volume of infarction,to detection the expression of HIF-la,VEGFand EPO in the hippocampus,to explore adenosine preconditioning protection on focal cerebral ischemia-reperfusion injury in rats.Methods1、Rat model of middle cerebral artery occlusion(MCAO) was established by suture-occluded method. We take120healthy male Sprague-Dawley rats with weighing250-280g, they were randomly divided into four groups,they were divided into sham operation group (F), adenosine pretreatment and sham group (AF), ischemia-reperfusion group (IR) and adenosine pretreatmentischemia-reperfusion group (AR). According to the reperfusion time on6h or12h or24h after MCAO, each group was further divided into three subgroups. Rats in group F and AF received the operations without ischemia by suture emboli. The24rats of each group with Homer’sign in right side and paralysis of the left front limb were observed to judge the success of MCAO model.2、 The rats with neurological behavior scores of the experimental rats in each goup were estimated after different reperfusion time.3、We detected the infarct volume after focal cerebral ischemia by TTC staining.4%The rats of focal cerebral ischemia with morphological changes of the neurons in the hippocampus were observed by HE staining.5、The each group rats at different time points by immunohistochemical detection the hippocampal the expression of HIF-1α and VEGF and EPO.Results1、Nerve damage symptoms and neurological behavior scoresThere were no symptoms of neurological deficit both in group F and AF.In other words, their neurological behavior scores were zero. However, in group IR and AR,there were varying degrees of nerve damage symptoms. At corresponding reperfusion point, all neurological behavior scores of rats in group AR were lower than group IR. The difference was statistically significant (P<0.05).2、TTC stainingThe ratsof F and AF groups with bilateral cerebral hemisphere did not see obvious infarcts, homogeneously red. The ratsof IR and AR group with right cerebral hemisphere are pale infarct area, mainly in the frontal and parietal cortex and striatum. Compared the AR group of cerebral infarction is decreased to the IR groupis significant difference (P<0.05).3、HE dyeingThe neurons of F and AF groups in the rat hippocampus cells closely packed, rules, neat, contour is clear, the cell body full, nuclear middle and nucleolus is clear, they did not see death of neurons and no abnormal morphological changes; the ratsof Ischemia6h, the hippocampus pyramidal cell layer of mild edema, some cells appeared to nucleus pycnosis, strong color; the rats of Ischemia reperfusionl2h and24h with the pathology trending down. Compared AR group with IR group in the same ischemia reperfusion time point has been improved the pathological changes of rats had12h with the objective improvementiy.4、HIF-la immunohistochemical stainingObserved the hippocampus HIF-1α after the immunohistochemical staining,it showed HIF-la positive cellsof F and AF groups are expressing rarely, the rats of IR group in ischemia reperfusion of6h and12h and24h,the HIF-1α expression increased, and reached a peak in12h, then they decrease dgradually; AR groups in different brain ischemia reperfusion time point HIF-1a express the IR group increased significantly (P<0.05).5、VEGF immunohistochemical stainingVEGFpositive cells of F and AF groups express weaked, VEGF in the hippocampus of IR group increased obviously, the AR group of in different brain ischemia reperfusion time point increased significantly to IR group (P<0.05).6、EPO immunohistochemical stainingEPO positive cells of F and AF group are rare, but in IR and AR groups, EPO positive cells express in different reperfusion time point influenced by the expression of HIF-1α positive cells express significantly, the rats of MCAO reperfusioned are expressed peak on12h, then less and less,compered AR with the IR group in the same reperfusion time positive cells expression is significantly higher (P<0.05).Conclusions1、Adenosine preconditioning reduce the rats in brain tissue damage of focal cerebral ischemia reperfusion significantly and can effectively improve neurologic injury symptoms caused by reperfusion.2%Adenosine preconditioning can increase the positive cells expression of HIF-1a, VEGF and EPO in the hippocampus of reperfusion brain.