VASCULAR ENDOTHELIAL GROWTH-FACTOR (VASCULAR-PERMEABILITY FACTOR) EXPRESSION IN INJURED RAT-BRAIN

We investigated the expression of vascular endothelial growth factor ( VEGF)/vascular permeability factor (VPF) in stab and freeze brain inju ry models in rats, Immunohistochemical staining with anti-VEGF antibod ies demonstrated an increase in VEGF-positive cells in and around both lesions, Morphologically, the injury-induced VEGF-positive cells rese mbled astrocytes, Double immunofluorescent staining for the astrocytic marker glial fibrillary acidic protein (GFAP) and VEGF demonstrated d irectly that VEGF-positive cells which appeared in response to these i njuries were astrocytes. VEGF expression in astrocytes was maximal on days 3 and 4 after injury in terms of both cell number and affected ar ea, The increase in VEGF-positive cells was more widespread in the fre eze lesion than in the stab wound, and occurred in both the lesioned a nd nonlesioned hemispheres, VEGF-positive cells were still present 3 w eeks after both injuries, but their numbers were reduced and their dis tribution became limited to the immediate vicinity of the lesions, The se observations indicate that astrocytes react to injury by increasing VEGF expression, suggesting that VEGF might participate in the centra l nervous system response to injury. (C) 1997 Wiley-Liss, Inc.