大鼠脑梗死后乏氧组织长时间存在与星形胶质细胞的关系

目的 探讨大鼠脑梗死后乏氧组织的长时间存在与星形胶质细胞的关系.方法 利用大鼠脑缺血1.5 h再灌注(1.5 h IR组)和持续缺血(PI组)的大脑中动脉闭塞模型,采用EF5和胶质纤维酸性蛋白(GFAP)免疫荧光双标方法观察乏氧组织和星形胶质细胞增殖活化情况,比较两组术后1、3、7、14d缺血侧大脑半球皮层的星形胶质细胞GFAP荧光强度以及与乏氧组织的关系.结果 1.5 h IR组术后1、3、7、14 d均见乏氧组织存在,PI组乏氧组织仅存在3 d.各观察时间点乏氧组织内的GFAP荧光强度均较周围区域高,差异有统计学意义(P<0.05).随着时间的延长,两组的GFAP荧光强度均不断增强,在术后7 d达到高峰,14 d时下降,差异有统计学意义(P<0.05);且各时间点的1.5 h IR组的GFAP荧光强度均高于PI组,差异有统计学意义(P<0.05).结论 脑梗死后星形胶质细胞在乏氧组织内增殖活化尤为明显,乏氧组织的长时间存在与星形胶质细胞密切相关.

Relationship between long-tern presence of hypoxic tissue and astrocyte activation after cerebral infarction in rats

Objective To explore the relationship between the long-term presence of hypoxic tissue and astrocyte activation after cerebral infarction in rats. Methods Middle cerebral artery occlusion was performed in rats to induce permanent brain ischemia (PI group) or transient isehemia for 1.5 h followed by reperfusion (1.5 h IR group). Double immunofluorescence staining with EF5 and gliai fibrillary acidic protein (GFAP) antibodies was used to observe the hypoxic tissue and status of astrocyte activation, respectively. On days 1, 3, 7 and 14 after the operation, GFAP fluorescence intensity and the presence of hypoxic tissue in the ischemic cortex were observed. Results The hypoxic tissues were present from day 3 to day 14 after the operation in 1.5 h IR group, but disappeared after day 3 in PI group. GFAP fluorescence intensity in the hypoxic tissue was significantly higher than that in the surrounding tissues at all the observation time points (P<0.05). GFAP fluorescence intensity increased progressive in both groups with the lapse of time (P<0.05), reaching the peak level on day 7 followed then by gradual declination. On each of the time points for observation, GFAP fluorescence intensity in 1.5 h IR group was significantly higher than that in PI group (P<0.05). Conclusion Astrocyte activation is especially obvious in the hypoxic brain tissues after cerebral infarction, which is closely associated with the long-term existence of hypoxic tissues.