大鼠持续脑缺血后星形胶质细胞的时空分布及其变化

Temporal and Spatial Distributions of Astrocytes after Permanent Local Cerebral Ischemia

目的本实验研究星形胶质细胞在持续脑缺血后的时空分布及其变化。方法选用SD雄性大鼠54只,随机分为分成假手术组和手术组。手术组又按缺血时间(3、6、12、24及48h)分为5个亚组。假手术组和每亚组各9只大鼠。采用颈内动脉线栓加环扎法复制大鼠持续脑缺血模型,相应时间点灌注取脑,常规固定包埋切片,HE和TdT介导的dUTP缺口末端标记(TUNEL)、胶质纤维酸性蛋白(GFAP)染色。结果随着持续脑缺血时间的延长,中心区神经细胞及星形胶质细胞的数量逐渐减少,缺血边缘区凋亡的神经细胞数量逐渐增多,而星形胶质细胞在12h达到最低点之后,数量逐渐增多,并呈空泡状改变。结论在持续缺血12h之后,缺血中心区与半暗带区星形胶质细胞数量变化不一致,在半暗带其数量逐渐增多,提示星形胶质细胞在缺血后的不同阶段,其作用可能不同。

Objective To observe the temporal and spatial distributions of astrocytes after permanent local cerebral ischemia. Methods Total 54 male SD rats were selected and randomly divided into 2 groups, sham-operation group and operation group. Depending on the time point from 3 hours to 48 hours, the operation rats were divided into 5 subgroups. Animal model of focal cerebral ischemia was established by nylon suture embolization and cerclage. The brain samples of each group were obtained at 3 h, 6 h, 12 h, 24 h and 48 h after embolization, respectively. Morphologic changes after hematoxylin and eosin(HE) dying, TdT-mediated dUTP-biotin nick end labeling (TUNEL) and glial fi brillary acidic protein(GFAP) immunohistochemistry analysis were observed. Imaging analysis technique was used to detect the temporal and spatial distributions of the astrocytes in each animal. Results As ischemic condition continued, both TUNEL and GFAP positive cells decreased in the core area of cerebral ischemia. And in the marginal area, the TUNEL positive cells increased with time passing by, while at 12-hour time point, the GFAP positive cells decreased mostly and then increased slowly. Conclusion At the time point of 12 hour of cerebral ischemia in the marginal area, the temporal and spatial distributions of astrocytes are not coincided with those of astrocytes in core area, which may mean that during different period of cerebral ischemia, astrocytes may play different roles.