Cerebral ischemic preconditioning increases the expressions of HIF-1αand VEGF in the cortex area of rats with focal cerebral ischemia/reperfusion injury / 医学研究生学报

ABSTRACT

Objective Cerebral ischemic tolerance induced by cerebral ischemic preconditioning has become a hotspot in the researches of ischemic cerebrovascular disease, and its specific mechanism remains to be clarified.This study was to explore the brain protection mechanisms of cerebral ischemic preconditioning by observing the expressions of HIF-1αand VEGF in the cortex area sur-rounding the infarct locus in rats with focal cerebral ischemia /reperfusion ( I/R) after cerebral ischemic preconditioning. Methods A total of 130 male SD rats were randomly divided into three groupssham operation, middle cerebral artery occlusion, and cerebral is-chemic preconditioning, the animals in the latter two groups subjected to 2, 6, 12, 24, 48 and 72 h of I/R.The expressions of HIF-1α and VEGF at different time points were detected by immunohistochemistry and Western blot. Results In the middle cerebral artery occlusion group, the expressions of HIF-1αand VEGF positive cells and proteins increased at 2 h after I/R, reached the peak at 24 h, and then gradually decreased to and at 72 h, but still higher than in the sham operation group (P<0.05).The expressions of HIF-1αand VEGF positive cells were significantly higher in the cerebral ischemic preconditioning than in the middle cerebral artery occlusion group (all P<0.05), so were the expressions of HIF-1αand VEGF positive proteins in the former group than in the latter (all P<0.05).The sham operation group showed only a little in-crease in the expressions of HIF-1αand VEGF positive cells and proteins. Conclusion Cerebral ischemia reperfusion injury induces the expressions of HIF-1αand VEGF, which can be further upregulated by brain ischemic preconditioning.