Investigation of Expression of Vascular Endothelial Growth Factor in Focal Cerebral Ischemia of the Rats

Objective To explore the expression of vascular endothelial growth factor at different time point after transient focal cerebral ischemia in order to understand the action of VEGF in ischmic brain.Methods The rats were subjected to embolic focal ischemia by placing homologous blood clots into the middle cerebral artery.The expressions of VEGF of all groups were analysed by immunohistochemistry at different time points after ischemia.Results Compared with the contralateral hemisphere,the expression of VEGF increased in the penumbra at 6h after MCAO and the highest expression occurred at 24 h after MCAO,followed by decreasing gradually to the normal level at 1 week.VEGF expressed mainly in neurons,glial cells and vascular endothelial cells in the penumbra.Angiogenesis was seen in the penumbra at 48 h after focal cerebral ischemia and reached the highest level at 1 week after ischemia.Conclusion VEGF expresses in neurons,glial cells and vascular endothelial cells at the early stage of focal cerebral ischemia.The expression speeds up the angiogenesis in the penumbra,improves blood provision and helps to recover nerve function.