局灶性脑缺血大鼠脑组织皮质运动区和海马星形胶质细胞的动态变化

目的 观察大鼠局灶性脑缺血后皮质运动区和海马星形胶质细胞的变化。方法 雄性SD大鼠144只，按随机数字法分成正常组、假手术组和手术组，每组48只。手术组用大脑中动脉电凝术(MCAO)建立局灶性脑缺血模型；假手术组的操作步骤和手术组相同，只是不将暴露的大脑中动脉凝闭；正常组不做任何处理。应用免疫组化检测正常组、假手术组以及手术组术后1、2、3、5、7、14、28、56 d皮质运动区和海马星形胶质细胞神经胶质酸性蛋白(GFAP)表达的变化。结果与正常组和假手术组比较，手术组大鼠缺血侧和健侧MCAO术后皮质运动区GFAP阳性细胞计数术后第1天明显降低，第3天开始升高，缺血侧和健侧分别于术后第7天、第5天升至最高(85.6±3.3、75.3±2.9)，随后逐渐下降并均在术后第14天出现第2个低谷，其后又开始逐渐上升接近正常。与正常组和假手术组比较，手术组海马CA1区GFAP阳性细胞计数缺血侧和健侧自术后第1天即开始升高，术后第7天升至最高( 106.5±3.6、108.4±3.0)，其后进入平台期；CA2区、CA3区缺血侧和健侧术后第3天开始明显升高，CA2区缺血及健侧最高值则分别出现在术后第5天(106.9±4.4)、第7天(107.5±3.8)；CA3区为第5天(130.9±3.7)、第5天(129.2±4.0)，术后第14天开始下降，但仍然高于正常组和假手术组。结论 大鼠局灶性脑缺血后，不同脑区星形胶质细胞的表达随时间变化的模式不同，在皮质运动区存在两谷一峰的现象，在海马表达逐渐增强，并维持在一个较高的水平，这种差别可能与不同脑区神经的可塑性有关。

Astrocyte changes over time in motor cortex and hippocampus of rat brain tissue after focal cerebral ischemia

Objective To observe the astrocyte changes over time in motor cortex and hippocampus of rat brain tissue after focal cerebral ischemia. Methods A total of 144 male SD rates were randomized into the normal group, sham-operatod group and operated group (n=48 each). The operated group received middle cerebral artery electrocoagulation (MCAO) for modeling of focal cerebral ischemia. The same procedure except for MCAO was given to the sham-operated group, while the control group did not undergo any treatment. On days 1, 2, 3, 5, 7, 14, 28 and 56 post-operation, the three groups were determined for expression of glial fibrillary acidic protein (GFAP) in astrocytes of the motor cortex and hippocampus.Results Compared with the control group and sham-operated group, the post-MCAO GFAP-positive cell count at cortical motor area of ischemia and uninjured sides in the operated group was remarkably reduced on day 1, then started to increase on day 3 and a peak was reached on days 7 (isehemia side, 85.6±3.3) and 5 (uninjured side, 75.3±2.9). Thereafter, the count gradually declined to a second trough on day 14 before slowly returning normal. Compared with the control group and sham-operated group, the post-MCAO GFAPpositive cell count in hippocampal CA1 area of ischemia and uninjured sides in the operated group started to increase and a peak was reached on day 7 (ischemia side, 106.5±3.6; uninjured side, 108.4±3.0), and then remained plateaued; the cell counts in hippocampal CA2 and CA3 areas of ischemia and uninjured sides started to increase on day 3 and a peak was reached on days 5 (ischemia side CA2, 106.9±4.4; ischemia side CA3, 130.9±3.7; uninjured side CA3, 129.2±4.0) and day 7 (uninjured side CA2, 107.5±3.8), then started to decline on day 14 but remained at higher levels as compared with the other two groups.Conclusions The post-MCAO expression of GFAP in astrocytes of different brain areas presents varied changes over time, with two troughs and one peak at cortical motor area, and gradual increase to a higher level at hippocampal areas. Such difference may be associated with varied plasticity of brain areas.