摘要
目的动态观察大鼠持续性局灶脑缺血后星形胶质细胞的形态学变化,探讨星形胶质细胞的死亡方式。方法将48只SD大鼠随机分为免疫组化组、免疫组化对照组、电镜实验组和电镜实验对照组。采用颈内动脉线栓并环扎的方法建立持续性局灶脑缺血模型。免疫组化组和电镜实验组大鼠按照缺血时间(3h、6h、12h、24h、48h)平均随机分为5个亚组。对照组为术后24h取脑。免疫组化标本采用HE染色及TUNEL-GFAP双染。电镜标本在中心区、边缘区分别取材、染色后,透射电镜观察。结果随着时间的延长,脑缺血中心区及边缘区星形胶质细胞逐渐出现核肿胀、染色质分散、边聚、空泡变,核膜破溃,染色质溢出。随着缺血时间延长,中心区GFAP阳性细胞数逐渐减少,直至基本消失。缺血边缘区则可见到GFAP阳性细胞数量逐渐增多。TUNEL-GFAP双染未见阳性细胞。结论持续局灶脑缺血后,星形胶质细胞未见凋亡,推测胀亡是星形胶质细胞主要的死亡方式。
Objective To explore a death mode of astrocytes after permanent local cerebral ischemia by observing morphologic changes of target cells. Methods Fourty-eight male SD rats were divided randomly into 4 groups： immunohistochemistry experimental group, immunohistochemistry control group, electron microscope experimental group, and electron microscope control group. The animal models of focal cerebral ischemia were established by nylon suture embolization and cerclage. The brain samples of immunohistochemistry experimental group and electron microscope experimental group were obtained at 3 h, 6 h, 12 h, 24 h and 48 h after embolization, respectively. The brain samples of two corresponding control groups were obtained at 24 h after embolization. HE dyeing and TUNEL-GFAP double labeled immunohistochemistry were applied in brain samples of immunohistochemistry experimental group and immunohistochemistry control group. The samples of electron microscopic groups were taken in the center and the marginal region for staining and observation under a transmission electron microscope. Results Microscopic and electron microscopic observation disclosed that astrocytes in both central and marginal regions became nucleus swollen along with nuclear membrane cracking and chromatin leaking as the time of ischemia went on. TUNEL or GFAP positive cells could be seen in both central and marginal regions 3 h after ischemia. As the ischemia persisted, GFAP positive cells in central region had become less and less, which can hardly be seen after 12 h. After 24 h ischemia, the structure of astrocytes in the central region had changed so much that it could hardly be identified. While in the marginal region, GFAP positive cells can be observed at 6 h and the number increased as time went on. At 24h GFAP positive cells in marginal region had increased so much that it had taken on an overt dividing line away fi＇om the central region. GFAP-TUNEL double positive cells were not observed in the study. Conclusion As no apoptosis was observed during permanent ischemia, oncosis may be the main death mode of astrocytes initiated by ischemia.
出处
《中华神经医学杂志》
CAS
CSCD
2005年第10期979-982,共4页
Chinese Journal of Neuromedicine
基金
广东省医学科研基金(A1998543)
