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目的评价脑缺血再灌注后基质金属蛋白酶(MMP-9)的表达在血脑屏障(BBB)变化中的作用以及与MRI表现之间的相关性。材料与方法40只雄性SD大鼠分为假手术组和缺血线栓法组建立大脑中动脉闭塞(MCAO)模型,根据再灌注时间点2h、6h、24h、48h、72h又分5小组。MRI上反映BBB变化指标包括T2WI异常高信号的相对信号强度、高信号体积及T1液体衰减反转恢复序列(FLAIR)强化程度。免疫组织化学法测定MMP-9的表达情况。各BBB变化的MRI指标与标本免疫组织化学MMP-9的表达结果行统计学相关分析。结果BBB变化的MRI指标T2WI相对信号强度、异常高信号体积、T1FLAIR强化程度与标本免疫组织化学MMP-9的表达结果呈正相关。结论缺血再灌注各时间点血管内皮细胞MMP-9表达增强与其BBB变化的MRI征象密切相关。
Objective To evaluate the role of matrix metalloproteinase (MMP-9) in the changes of the blood-brain barrier (BBB) after cerebral ischemia-reperfusion and its correlation with MRI findings. MATERIALS AND METHODS: Forty male SD rats were divided into sham-operation group and ischemia-occlusion group. Middle cerebral artery occlusion (MCAO) model was established. The rats were divided into 5 groups according to the reperfusion time points of 2h, 6h, 24h, 48h and 72h. The indicators of BBB change on MRI include the relative signal intensity of T2WI abnormal high signal, the high signal volume and the intensification of T1 fluid attenuated reverse recovery sequence (FLAIR). The expression of MMP-9 was detected by immunohistochemistry. The correlation between BBB changes of MRI and immunohistochemical expression of MMP-9 were statistically analyzed. Results The changes of T2WI signal intensity, abnormally high signal volume and the intensity of T1FLAIR were positively correlated with the expression of MMP-9 in BBB specimens. Conclusion The increased expression of MMP-9 in vascular endothelial cells at various time points after ischemia-reperfusion is closely related to the MRI signs of BBB changes.