Abstract: Objective To observe the effect of mild hypothermia on expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) in brain tissues in rats with cerebral ischemia-reperfusion. Methods Thirty Sprague-Dawley rats were randomly divided into sham group, model group and mild hypothermia group with ten rats in each group. The latter two groups were established middle cerebral artery occlusion (MCAO) for two hours and reperfusion model. The mild hypothermia group received mild hypothermia treatment for 24 hours. The neurologic function was evaluated with Longa's score. The brain water content was measured by wet/dry method. The infarction area ratio was assessed by TTC staining. The protein levels of VEGF and HIF-1α were determined by ELISA, while the mRNA level of VEGF was assessed by qPCR. Results Compared with the sham group, the score of neurologic score, the brain water content ratio and the infarction area ratio, the expression of VEGF protein and HIF-1α protein, and the mRNA level of VEGF increased in the model group (P<0.05). Compared with the model group, the score of neurologic score significantly decreased (χ²=26.657, P<0.001), the brain water content ratio and the infarction area ratio decreased (P<0.05), and the expression of VEGF protein and HIF-1α protein, and the mRNA level of VEGF further increased (P<0.05) in the mild hypothermia group. Conclusion Mild hypothermia may protect against ischemic-induced neurologic injury by up-regulating the expression of VEGF and HIF-1α, and promote the angiogenesis in the rats with cerebral ischemia-reperfusion.

Key words: ischemia-reperfusion, mild hypothermia, vascular endothelial growth factor, hypoxia-inducible factor-1α, rats