短暂性脑缺血大鼠模型的水通道蛋白磁共振分子成像研究

摘要

Objective:Sought to discern the changes in aquaporin magnetic resonance molecular imaging (AQP MRI) parameter after experimental stroke.Materials and Methods:Thirty-one adult SD male rats were randomly divided into two groups:ischemia group which underwent 1 h right middle cerebral artery occlusion (MCAo)and sham group.T2 FLAIR,conventional DWI and AQP MRI examination was executed 48 h after reperfusion.And AQP4 expression was detected by Westem blot and immunofluorescence.Results:The percent change of T2 values of lesions in ischemia group was increased up to 56.655±7.359,which was much higher than that of sham group (vs 2.334±2.203,P＜0.01),whereas the homologous ADC values were remarkably decreased (-24.491±1.924 vs-0.960±3.824,P＜0.01).Result of AQP MR[showed that the percent change ofAQP ADC of ischemia group was significantly decreased than that of sham group(-25.218±8.839 vs 0.209±1.279,P＜0.01).Western blot result showed that the AQP4 expression in affected side of ischemia group was higher than that of sham group.Contrastive analysis showed that areas with high AQP ADC values presented low positive staining of AQP4 in immunofluorescence,and areas with low AQP ADC values presented high positive staining.Conclusions:AQP MRI could display the distribution of aquaporin in vivo,which would be of great importance to assess progression of cerebral ischemia.%目的 探讨缺血性脑卒中大鼠模型在水通道蛋白磁共振分子成像(AQPMRI)上的改变.材料与方法 31只成年雄性SD大鼠随机分为两组,实验组和假手术组.实验组经历1h的右侧大脑中动脉栓塞建立短暂性脑缺血模型.在恢复再灌后48 h行MRI检查采集T2 FLAIR、常规DWI及AQP MRI图像,并行WesternBlot和免疫荧光检测AQP4的表达量.结果 实验组大鼠在T2 FLAIR上可见明显的高信号病灶,其T2信号的差值百分比显著高于假手术组(56.655±7.359和2.334±2.203,P＜0.01);实验组病灶的ADC值差值百分比较假手术组显著降低(-24.491±1.924和-0.960±3.824,P＜0.01);AQP ADC结果显示实验组的AQPADC值的差值百分比较假手术组显著降低(-25.218±8.839和0.209±1.279,P＜0.01).Western Blot结果显示实验组患侧的AQP4蛋白表达量显著高于假手术组.将实验组单只大鼠的AQP ADC图像与其相应的免疫荧光结果对比显示,AQPADC值高的区域,AQP4阳性染色减少,而AQP ADC值低的区域,AQP4阳性染色增多.结论 AQP MRI能够在体显示水通道蛋白的分布情况,对缺血性脑卒中的病程判断具有重要意义.