银杏内酯B对局灶性脑缺血时星形胶质细胞GFAP表达的影响

目的 观察血小板活化因子(PAF)受体拮抗剂银杏内酯B(GB)对局灶性脑缺血时星形胶质细胞胶质纤维酸性蛋白(GFAP)表达的影响,并探讨其作用机制.方法 建立光化学诱导树局灶性脑缺血模型,用HE染色和电镜技术观察缺血后不同时间脑组织星形胶质细胞的形态学改变;用免疫组织化学法观察脑缺血后4 h、24 h、72 h及给予GB后24 h半暗区及对侧皮层星形胶质细胞GFAP的表达,并测定其平均灰度值.结果 光镜下可见,HE染色显示树局灶性脑缺血后,随缺血时间延长,星形胶质细胞形态有不同程度改变;电镜观察显示缺血24 h时星形胶质细胞明显肿胀.免疫组织化学染色可见,半暗区星形胶质细胞GFAP表达在4 h时没有明显改变, 24 h时增加 (P＜0.01),72 h时仍维持在较高水平(P＜0.01);对侧皮层星形胶质细胞GFAP表达于72 h时开始增加(P＜0.05).缺血后6 h舌下静脉注射GB至缺血24 h时,星形胶质细胞GFAP表达少于缺血组(P＜0.05),但仍较假手术组高.结论 脑缺血后星形胶质细胞GFAP表达增强,GB可通过减少星形胶质细胞GFAP的表达而起脑保护作用.

The Effect of Ginkgolide B on Astrocyte GFAP Expression after the Focal Cerebral Ischemia

OBJECTIVE: To observe the effect of platelet activating factor (PAF) antagonist, ginkgolide B (GB), on the expression of glial fibrillary acidic protein (GFAP) in astrocytes during focal cerebral ischemia, of which the mechanism will be explored too. METHODS: The focal cerebral ischemia of tree shrews was induced to form via photochemical reaction. Morphological changes were observed by hematoxylin-eosin staining and electron microscopic technology. The GFAP expression in astrocytes was detected by immunohistochemistry. RESULTS: Morphological changes of the brain tissue occurred after focal cerebral ischemia. Astrocytes were more swollen with the prolongation of ischemia. The GFAP expression in astrocytes in the penumbra didn't change obviously at 4 h, but increased significantly at 24 h (P < 0.01), and retained the higher level at 72 h (P < 0.01) after focal cerebral ischemia. Whereas in contralateral cortex, the GFAP expression began to increase at 72 h (P < 0.05) after focal cerebral ischemia. With giving experimental animals GB at 6 h, the GFAP expression decreased until at 24 h after focal cerebral ischemia. CONCLUSION: GFAP expression in astrocytes increases after focal cerebral ischemia. And by inhibiting the astroglial GFAP expression, the ginkgolide B exerts the cerebral protective effects.