DWI及PWI评价NO前体/供体介入给药对局灶性脑缺血的保护作用

目的 建立大鼠大脑中动脉阻断(MCAO)模型,颈内动脉局部给予NO前体L-精氨酸(L-Arginine,ARG)、NO供体硝酸甘油(NG),并通过DWI及PWI动态评估大鼠受累脑区血循环与脑损害变化,探讨脑缺血早期ARG和NG的保护作用.方法 雄性SD大鼠采用线栓法阻塞右侧大脑中动脉,制作成缺血2 h再灌注模型,并于再灌注即刻患侧颈内动脉分别给予L-ARG、NG,在缺血2 h、再灌3和24 h分别进行T1WI、T2WI、DWI和PWI影像学评估,并与Longa评分、红四氮唑(TTC)染色观察对比.结果 给药组DWI高信号区及TTC苍白区较MCAO组减小(P＜0.01);从缺血2 h到再灌24 h,各组大鼠DWI高信号区的ADC、rADC值均呈现升高趋势,再灌3和24 h时,给药组大鼠DWI高信号区的ADC、rADC值比MCAO组升高(P＜0.01).结论 DWI及PWI证实脑缺血超早期NO前体/供体局部介入给药具有显著的脑保护作用.

Evaluation of the protective function of NO precursor/donator on cerebral ischemia injury with DWI and PWI

Objective To establish a rat model of middle cerebral artery occlusion (MCAO)by blockage or obstruction of middle cerebral artery. NO precursor L-Arginine (L-ARG) and NO donator Nitroglycerine (NG)are administrated from intraearotid arteries. DWI and PWI are applied to evaluate blood circulation and brain damage of the effected region to elucidate the piotective function of L-ARG and NG in the early stage of brain ischemia. Methods The middle cerebral artery was occluded by insertion of a suture through the internal carotid artery of SD male rats to duplicate ischemia-reperfusion model. Reperfusion was established by suture withdrawal. After 2 hours of blockage, reperfusion and administrate L-ARG,NG by interventional therapy through the internal carotid artery simultaneously. Image indexes such as T1WI, T2WI, DWI and PWI are utilized to assess the changes in different time points. These indexes, Longa score and TTC stain were compared. Results There were obvious decrease in DWI high signal region and Trc pale region in drugs groups, compared with MCAO group(P＜0.01).ADC and rADC values in DWI high signal region increased gradually from 2 hours after ischemia to 24 hours after reperfusion in each group. ADC and rADC values in DWI high signal region of the drugs groups increased obviously(P＜0.01).Conclusion Interventional therapy with NO precursor/donator showed significant protective function in the early stage of brain ischemia.