急性脑缺血大鼠外周血内皮祖细胞研究

Study on peripheral blood endothelial progenitor cells in rats with acute brain ischemia

目的观察急性脑缺血大鼠外周血内皮祖细胞数目的变化，探讨其在缺血性脑血管病发生、发展中的病理生理学机制。方法30只健康雄性老年Wistar大鼠，随机分为假手术组、缺血组和缺血．再灌注组。建立大脑中动脉闭塞模型，密度梯度离心获得外周血单个核细胞，流式细胞术检测CD34和CD133表达水平。结果不同处理组大鼠各时间点外周血内皮祖细胞数目比较，差异具有统计学意义（均P〈0．05）。手术后24h，缺血组和缺血．再灌注组大鼠外周血内皮祖细胞数目减少至最低水平（均P〈0．05），且以缺血组更为明显（P〈0．05）；至手术后7d，缺血．再灌注组大鼠外周血内皮祖细胞数目恢复至正常值范围（P〉0．05）；至手术后10d，缺血组方恢复至正常值水平（P〉0．05）。结论老年大鼠急性脑缺血早期即出现外周血内皮祖细胞数目显著减少，其中以缺血组细胞数目减少更为明显，且恢复至正常值范围的时间较缺血．再灌注组延长。

Objective To investigate the changes in number of peripheral blood endothelial progenitor cells （EPCs） in rats with acute brain ischemia, and to explore the pathophysiological mechanism of EPCs in the occurrence and development of ischemic cerebral vascular diseases. Methods Thirty old male healthy Wistar rats were randomly divided into 3 groups： sham-operation group, brain ischemia group and ischemiareperfusion group. Middle cerebral artery occlusion （MCAO） model was established by modified Longa method. The mononuclear cells from peripheral blood were obtained by density gradient centrifugation. The expressions of CD34 and CD133 were detected by flow cytometry. Results There was significant difference in the number of peripheral blood EPCs among 3 groups in different time points （P〈 0.05, for all）. The number of peripheral blood EPCs was significantly lower in brain ischemia group and ischemia-reperfusion group than that in sham-operation group at 24 h after operation （P〈 0.05, for all）. The number of peripheral blood EPCs in brain ischemia group was the lowest （P〈 0.05）. The number of peripheral blood EPCs in ischemia- reperfusion group achieved to normal level at 7 d after operation （P〉 0.05）, but in brain ischemia group did not reach to normal level until 10 d after operation （P〉 0.05）. Conclusion The number of peripheral blood EPCs decreases significantly in old acute brain ischemia rats at early stage. The decreasing of peripheral blood EPCs is more significant in ischemia group, and the time recovering to normal level is longer than that in ischemia-reperfusion group.