大鼠脑缺血血管内皮生长因子与NG2细胞增殖关系的初步研究

Role of VEGF in NG2 cells proliferation in rats after cerebral ischemia

目的观察大鼠脑缺血后少突胶质前体细胞(oligodendrocyte progenitor cells,OPC)的表达,并初步探讨血管内皮生长因子(vascular epithelial growth factor,VEGF)在其中的作用。方法实验动物72只,按随机数字表法分为假手术对照组、缺血组和缺血+贝伐单抗组共3组,每组设6、12、24、72 h 4个时相点,每个时相点6只大鼠,采用激光共聚焦观察缺血后不同时相点NG2和VEGF免疫荧光标记的细胞增殖状况。结果在大脑皮层区,NG2与VEGF标记细胞基本完全重叠。在缺血后72 h内,阳性标记细胞随时间延长,进行性增多,其中贝伐单抗组在各时相点的双阳性细胞数均明显少于缺血组(P<0.05)。结论脑缺血损伤后脑皮层区存在OPC的活化现象。VEGF可能对损伤后NG2的增殖有促进作用。

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 which 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（P0.05）.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.