Vascular endothelial growth factor expression in transient focal cerebral ischemia in the rat.

Vascular endothelial growth factor (VEGF) has been implicated in hypoxia-induced angiogenesis in tumors and ischemia. We examined VEGF mRNA and protein expression after occlusion of the middle cerebral artery (MCA) in rats. VEGF mRNA expression studied by in situ hybridization was increased in the ischemic border zone 24 h after 30, 60 or 120 min of focal cerebral ischemia. VEGF protein expression measured by Western blots was also increased in this region 24 and 48 h after ischemia, and VEGF immunocytochemistry localized this increased expression to astroglia. Thus, VEGF is induced after focal cerebral ischemia and could have a role in pathophysiology and recovery in the ischemic border zone.