局灶性脑缺血耐受和星形胶质细胞反应

目的　研究短暂性局灶性脑缺血预处理对永久性局灶性脑缺血的保护作用 ,及最佳预处理时间剂量 ,并探讨星形胶质细胞在脑缺血耐受中的反应。方法　采用开颅方法阻断大鼠大脑中动脉 ,通过观察大鼠脑梗死后神经功能损伤状况、脑梗死体积分析及病理形态学变化 ,评价不同的缺血预处理时间剂量 (10分钟、2 0分钟、30分钟 )对永久性局灶性脑缺血的保护作用。采用胶质纤维酸性蛋白 (GFAP)免疫组化法观察星形胶质细胞在脑缺血耐受中的反应。结果　与对照组相比 ,缺血预处理 2 0分钟未引起明显的神经元损伤 ,但使永久性局灶性脑缺血后神经功能损伤减轻 ,梗死体积明显减小 (P <0 .0 1)。免疫组化显示 ,2 0分钟缺血预处理组及重复缺血组星形胶质细胞在损伤预处理侧广泛激活。结论　 2 0分钟局灶性脑缺血预处理能够有效诱导脑缺血耐受。星形胶质细胞的激活可能与脑缺血耐受中神经元的存活相关。

The tolerance of focal cerebral ischemia and astroglial reaction

Objective To investigate the protective role of transient focal ischemic precondition(PC) against permanent focal cerebral ischemia, to define the proper time dose for precondition, and to study the reaction of astroglia in cerebral ischemic tolerance. Methods Temporary middle cerebral artery occlusion(10 minutes, 20 minutes, 30 minutes) followed three day reperfusion before permanent middle cerebral artery occlusion(PMCAO) transcranially was used as precondition in Wistar rats. The protective role was evaluated by observing the neurological deficits, analyzing the infarct volume and studying changes of pathohistology. The reaction of astroglia was observed by using anti GFAP immunohistochemistry.Results Compared with the control group, 20 min ischemic precondition, which did not produce neuronal damage obviously, alleviated the neurological deficits and reduced the infarct volume significantly( P <0.01) after PMCAO. Immunostaining using anti GFAP revealed GFAP protein extensively increased in PC cortex in 20 min precondition group and repeated ischemic group with 20 min precondition.Conclusion Ischemic precondition of 20 min is able to induce cerebral ischemic tolerance effectively. Astroglial activation may have relative to neuronal survival in ischemic tolerance.