缺血预处理后海马CA_1区反应性星形胶质细胞增生与迟发性神经元缺血耐受性的关系

Relationship between reactive astrogliosis and delayed neuronal ischemic tolerance by preconditioning ischemia in hippocampal CA_1 region

目的 探讨缺血预处理后海马 CA1 区反应性星形胶质细胞增生与迟发性神经元缺血耐受性的关系。方法 实验动物被随机分为假手术组、缺血组、预缺血组、预缺血后再缺血组。阻断沙土鼠双侧颈总动脉造成前脑缺血模型。采用细胞特异性抗原胶质纤维酸性蛋白 (GFAP)免疫组化法标记星形胶质细胞。结果预缺血后 1～ 7天 ,海马 CA1 区 GFAP阳性的星形胶质细胞数轻度增加 ,至 2 8天时增生非常显著 (P<0 .0 1)。预缺血后 1～ 7天再缺血 ,海马 CA1 区存活正常神经元数逐渐下降 ,预缺血后 2 8天再缺血又显著增加 (P<0 .0 1)。结论 缺血预处理后 ,神经元可出现迟发性缺血耐受 。

Objective To explore the relationship between reactive astrogliosis and delayed neuronal ischemic tolerance by preconditioning ischemia in gerbil hippocampal CA 1 region.Methods All gerbils were divided randomly into sham operation group,cerebral ischemia group and preconditioning ischemia group and preconditioning ischemia plus subsequent ischemia group. Transient forebrain ischemia model was induced by bilateral carotid occlution in gerbils. Immunohistochemistry for cell specific markers (glial fibrillary acidic protein(GFAP)was used to identify astrocyte.Results The numbers of GFAP positive astrocyte in hippocampal CA 1 region increased slightly at 1~7days following preconditioning ischemia, but increased significantly at 28 days after preconditioning ischemia ( P <0.01).When the subsequent ischemia was induced at 1~7 days following preconditioning ischemia,the numbers of survived normal neuron were reduced gradually in hippocampal CA1 regin,but increased remarkable at 28 days after preconditioning ischemia( P <0.01).Conclusion Reactive astrogliosis might play an important role in the delayed neuronal ischemic tolerance following preconditioning ischemia.