Effects of focal ischemic preconditioning on the expression of HIF-1αand VEGF in ischemia hippocampus CA1 region after focal cerebral ischemia/reperfusion in rats / 天津医药

ABSTRACT

Objective To observe the changes of ischemic preconditioning on the expression of hypoxia inducible fac?tor (HIF)-1αand vascular endothelial growth factor (VEGF) in ischemia hippocampus CA1 region after focal cerebral isch?emia/reperfusion (I/R) in rats, and the mechanisms of brain protection from brain ischemia preconditioning (BIP) thereof. Methods The male SD rats were randomly divided into three groupssham operation (SO) group,middle cerebral artery oc?clusion (MCAO) group and brain ischemia preconditioning (BIP) group. The MCAO group and BIP group were further divid?ed into six subgroups according to perfusion time after I/R including 2 h, 6 h, 12 h, 24 h, 48 h and 72 h. The ischemia pre?conditioning model rats were established. Immunohistochemistry and Western blot assay were used to observe the expres?sions of HIF-1αand VEGF in ischemia hippocampal CA1 region. Results Neurological function deficit was not observed in SO group. Compared with MCAO group, there was a lower neurological function deficit score in BIP group. In MCAO group and BIP group, the expressions of HIF-1αand VEGF positive cells and protein increased at 2 h after I/R, then gradu?ally increased from 6 h to12 h and reached the maximum level at 24 h, then gradually decreased. The levels were still higher at 72 h than those of SO group. The number of HIF-1αand VEGF positive cells and protein were significantly increased in MCAO group and BIP group than that of SO group (P<0.05). The number of HIF-1αpositive cells was higher in BIP group than that in MCAO group except 2 h and 6 h reperfusion groups. The expression of VEGF positive cells, HIF-1αand VEGF protein were significantly higher in BIP group than those in MCAO group at different time points (P < 0.05). Conclusion Ischemic preconditioning plays a protective role in brain, which may be related to up-regulation of HIF-1αand VEGF.