持续脑缺血后半暗带区星形胶质细胞的转归

Outcome of Astrocytes in the Penumbra under Sustained Cerebral Ischemia

目的探讨持续脑缺血状态下半暗带区星形胶质细胞的转归。方法 32只雄性SD健康清洁级大鼠,分为3组:正常对照组、假手术组、实验组。应用大脑中动脉阻塞模型(MCAO)在实验组诱导脑缺血发作。在MCAO后6、24h分别进行行为学神经功能评分,苏木精-伊红染色、Cresyl Violet染色和GFAP、Caspase-3、Porimin、DAPI免疫荧光染色。结果相对于正常对照组,假手术组无行为学改变,MCAO 6h组与MCAO 24h组均有明显行为学异常,提示造模成功。Cresyl Violet及苏木精-伊红染色显示缺血中心区脑组织坏死,缺血半暗带区细胞水肿,可见肿胀的星形胶质细胞,MCAO 24h组细胞损伤重于MCAO 6h组。荧光免疫检测显示,在MCAO 24h后半暗带区Porimin、GFAP和DAPI三标阳性细胞数目显著多于Caspase-3、GFAP和DAPI三标阳性细胞数目(P<0.05)。结论持续缺血的时间越长,脑损伤越严重,而缺血半暗带区星形胶质细胞多以细胞膜破坏、细胞肿胀为特征的胀亡方式走向死亡。

Objective To investigate the outcome of astrocytes in the penumbra under sustained cerebral ischemia.Methods A total of 32 male SD rats were divided into three groups：normal control group,sham operation group,experiment group.Cerebral ischemia was induced in the sham operation group and the experiment group by occluding the middle cerebral artery.Six and 24 h after middle cerebral artery occlusion（MCAO）,the behavior and neurological function scores were evaluated,and HE staining,Cresyl violet staining,and immunofluorescence staining for glial fibrillary acidic protein（GFAP）,Caspase-3,Porimin,4＇,6-diamidino-2-phenylindole（DAPI） were performed.Results There were no behavioral changes in the sham operation group compared with the normal control group.Significant behavioral abnormalities were found 6 and 24 h after MCAO.The animal model was built successfully.Cresyl violet staining and HE staining showed the necrotic brain tissue in the center of ischemic areas,cell edema and astrocyte swelling of astrocytes in ischemic penumbra.The cell damage was more severe in the 24 h MCAO group than in the 6 h MCAO group,Immunofluorescence staining found that in the ischemic penumbra,the number of Porimin-,GFAP-and DAPI-positive cells was significantly greater than that of Caspase-,GFAP-and DAPI-positive cells in the 24 h MCAO group（P〈0.05）.Conclusion Severe brain injury develops with the ischemic time.In ischemic penumbra,oncosis is the main death mode of astrocytes,characterized by the cell membrane damage and cell swelling.