银杏内酯B对树鼩血栓性脑缺血后GFAP表达的影响及机制探讨

目的:观察树鼠句血栓性脑缺血形成后不同部位星形胶质细胞表达胶质纤维酸性蛋白(GFAP)的时间消长改变,以及血小板活化因子(PAF)受体拮抗剂银杏内酯B(GB)对GFAP表达的影响,并探讨其可能机制。方法:建立光化学诱导树鼠句血栓性脑缺血模型,用免疫组化法检测缺血后4、2 4、72hGFAP表达,最后用图像分析系统测定其平均灰度。结果:脑缺血后半暗区GFAP表达增多,以2 4h最为显著,其平均灰度值为6 0 .33±3 .0 9(P <0 . 0 1) ,72h表达仍高,其平均灰度值为6 0. 88±2 . 6 2 (P <0 . 0 1) ,此时对侧及远隔区GFAP表达增强。光化学反应后6h于舌下静脉注射GB(5mg/kg) ,发现缺血后2. 4h半暗区星形胶质细胞GFAP表达明显下调,与对照组相比有显著差异(P <0 . 0 5 )。结论:缺血性脑损伤后星形胶质细胞表达GFAP增多与神经元受损有关;GB通过拮抗血小板活化因子(PAF)对神经元的损伤作用使星形胶质细胞表达GFAP减少。

Effects of ginkgolide B on glial fibrillary acidic protein expression after thrombotic cerebral ischemia in tree shrews

AIM: The present study was designed to ex amin e the changes in glial fibrillary acidic protein (GFAP) expression during cerebr al ischemia and the effects of ginkgolide B on GFAP expression. METHODS: The focal thrombotic cerebral ischemia was formed by ph otochemistry-induced in tree shrews. GFAP stained by ABC immunohistochemistry an d absorbance were measured with image analyze system. RESULTS: GFAP expression in astrocytes increased significantly ( P<0.01) at 24 h and kept in higher level at 72 h (P<0.01) within penu mbra after focal cerebral ischemia. GFAP expression declined when the animals we re given GB at 6 h after thrombotic cerebral ischemia. CONCLUSIONS: Neuronal necrosis resulted in GFAP expression in as tr ocytes after local cerebral ischemia and GB protected neurons by antagonizing PA F receptor and inhibiting GFAP expression.