Objective  To observe the reactive changes of oligodendrocyte progenitor cells (OPCs) in rats after cerebral ischemia

and explore the effects of vascular epithelial growth factor (VEGF) in these cells. Methods  Totally 72 rats were randomly divided into sham-operation control (SC) group

ischemia group and ischemia+bevacizumab group (2 mg/kg

intraperitoneally injected after the operation). The ischemia model was established by bilaterally ligating common cervical artery. The 6 animals of each group were sacrificed respectively in 6

12

24 and 72 h after the operation and their brains were resected for fixation to make frozen sections. The proliferation of cortex cells whi

ch were immunofluorescent double labeled with neuron-glia antigen 2 (NG2) and VEGF was detected by confocal laser scanning microscopy. Results  In the region of cerebral cortex

the positive cells labeled with NG2 and VEGF were fully overlapped under a fluorescent microscope. The amount of positive cells was gradually increased with prolongation of ischemic duration. While after bevacizumab treatment

the positive cells of double immunofluorescent labeling were obviously decreased than those in ischemia group (

P

<

0.05). Conclusion  OPCs significantly proliferate in the cortex of rats after cerebral ischemia. VEGF may play an important role in the proliferation of NG2 positive cells after brain injury.