大鼠急性期缺血再灌注血管原性脑水肿MRI表现及与血管内皮细胞明胶酶B表达的关系

MRI manifestations of vasogenic brain edema of acute ischemia/reperfusion of rats and the relationship between it and gelatinase B expression of vascular endothelium

目的 探讨脑缺血再灌注后血管原性脑水肿 (VBE)MRI表现及其与血管内皮细胞明胶酶B表达的相关性。方法 线栓法建立大鼠脑缺血再灌注模型 ,MR连续动态观察缺血区体积与信号变化 ,免疫组织化学方法观察血管内皮细胞明胶酶B表达。结果 缺血后 3h至 7d扫描术侧大脑半球见T2 高信号改变 ,12h至 3d见不同程度同侧侧脑室受压变窄、中线结构向对侧移位。 3h开始上述征象逐渐明显 ,1～ 2d达到峰值 ,3～ 7d则逐渐减轻。显微镜下见随时间推移而明显的血管内皮细胞肿胀、血管周围间隙增宽与无定形嗜酸物质。不同时间点明胶酶B免疫组织化学染色均可见血管内皮细胞胞质着色 ,12h、1d、2d、3d、5d与 7d染色评分分别为 (1 2 0± 0 4 2 )分、(1 70±0 4 8)分、(2 2 0± 0 71)分、(2 87± 0 5 8)分、(3 0 0± 0 0 1)分与 (2 5 0± 0 71)分 ,与MRI上缺血侧大脑半球体积增加、对侧大脑半球压迫、缺血侧T2 WI上异常高信号体积增加、缺血侧额顶叶和基底节区T2 WI信号强度 (SI)增加的相关系数为 0 89～ 0 976。结论 缺血再灌注后VBEMRI表现为脑组织体积增大与T2 WI信号增高。VBE的MRI征象与脑组织明胶酶B的表达有相关性。

Objective To explore MRI findings of vasogenic brain edema (VBE) in ischemia/reperfusion of rats, and to investigate the correlation between these findings and gelatinase B expression of vascular endothelium. Methods Thread occulsion of the right middle cerebral artery (MCAO) was made to set up VBE models in rats. Successive evaluation with MRI was performed to evaluate volume and signal intensity of infracted parenchyma. The specimen was analyzed at different time points immunohistochemically. Results High signal intensity was detected in the right middle cerebral artery territories on T 2WI 3 h to 7 d after MCAO. On T 2WI, from 12 h to 3 d, the compression of ipsilateral ventricle and displacement of midline structures were found. From 3 h to 2 d after ischemia, the signs of VBE accentuated gradually with a peak on 1st d to 2nd d. From 3 d to 7 d, these MRI signs eased gradually. Swelled endothelium, enlarged extravascur space, and inmorphological esophilic matter were presented. Positive plasma brown stain was detected in vascular endothelium. The score of positive stain of endothelium plasma at 12 h, 1 d, 2 d, 3 d, 5 d, and 7 d were 1.20±0.42, 1.70±0.48, 2.20±0.71,2.87±0.58, 3.00±0.01, and 2.50±0.71, respectively. These scores correlated well with MRI signs of VBE and the correlation coefficient was 0.890 to 0.976. Conclusion The MRI findings of VBE in acute ischemia/reperfusion of rats include increasement of the volume of infracted brain and hyperintensity on T 2WI. Gelatinase B expression of vascular endothelium was positive correlated with MRI signs of VBE.