缺血性脑损伤诱导内源性神经干细胞的增殖和迁移

Proliferation and transference of endogenous neural stem cells following ischemic brain injury

目的:观察缺血性脑损伤对内源性神经干细胞增殖、迁移的影响。方法:实验于2004-09/2005-03在新乡医学院人体解剖与组织胚胎重点实验室进行。10～12周体质量300～350g的健康雄性SD大鼠62只,由新乡医学院实验动物中心提供。按随机数字表方法将其分为正常组6只、假手术对照组14只、脑缺血再灌注组42只(分为再灌注1,3,5,7,10,15,20d7个时间点,每时间点6只)。参照Pulsinelli-Brierley法,夹闭大鼠双侧颈总动脉制作短暂性全脑缺血动物模型,全脑缺血10min后再灌注,假手术对照组不夹闭颈总动脉。于脑缺血再灌注不同时间点应用SABC免疫组化法染色显示5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞,光镜下观察并分析脑缺血损伤后内源性神经干细胞增殖、迁移的变化过程。结果:正常组、假手术对照组大鼠均存活,脑缺血再灌注组大鼠1d、5d、15d、20d各死亡1只,共58只大鼠进入结果分析。①正常组与假手术对照组室管膜下区、海马CA1区、齿状回区域均偶见5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞。②脑缺血再灌注后1d于海马、齿状回和室管膜下区均有5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞,随后逐渐增加,7～10d达高峰,术后20d仍有表达;在室管膜下区的5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞有向皮质、海马迁移的现象。结论:成年大鼠全脑缺血后7～10d内源性神经干细胞增殖达到高峰;增殖的内源性神经干细胞存在由增殖区向靶区迁移的现象。

AIM： To observe influences of ischemic brain injury on proliferation and transference of endogenous neural stem cells. METHODS： The experiment was carried out at Key Laboratory of Human Anatomy and Histology artd Embryology, Xinxiang Medical College from September 2004 to March 2005. Totally 62 healthy male SD rats aged 10-12 weeks, with the body mass of 300-350 g provided by Experimental Animal Center, Xinxiang Medical College. The rats were divided according to random digits table： normal group （n =6）, sham operation group （n =14）, cerebral ischemia/reperfusion group （n =42, every rats were reperfused after 1,3,5,7,10,15o20 days, respectively, 6 rats in each time point）. Animal model of transient total cerebral ischemia was created by means of Pulsinelli-Brierley. Brain was reperfused after cerebral ischemia for 10 minutes. Common carotid artery was not occluded in the sham operation group. Nestin and BrdU positive cells were stained by the methods of StreptAvidin Biotin Complex （SABC） and the cells were collected at different times after cerebral ischemia reperfusion. The proliferation and transference of endogenous neural stem cells were observed and analyzed under light microscope. RESULTS： Rats in the normal group and sham operation group were all survival, while one rat in the cerebral ischemia/reperfusion group died at days 1, 5, 15 and 20, respectively. Totally 58 rats were involved in the result analysis. ①There were rare BrdU and Nestin positive cells at subependymal zone, hippocampus CA1 region and dentate band region in normal group and sham operation groups. ②BrdU and Nestin positive cells appeared in the hippocampus, dentate band and subependymal zone after 1-day cerebral ischemia/reperfusion, and the expression level achieved the summit after 7-10 days of operation, and the expression could still be detected after 20 days of operation. Some BrdU and Nestin positive cells migrated to brain mantle and hippocampus at subependymal zone. CONCLUSION： The proliferation Of endogenous neural stem cells achieves the summit 7-10 days after total cerebral ischemia of male rats. The proliferative nerve stem cells can migrate to target region.