磁共振成像评价常压高浓度氧对大鼠脑缺血的保护作用

Neuroprotection of high concentration normobaric oxygen in stroke rat model observed with MR diffusion-weighted imaging

目的利用磁共振弥散加权成像(DWI)评价常压高浓度氧(NBO)对大鼠脑缺血的保护作用。方法选择雄性SD大鼠16只,采用线栓法制作右侧大脑中动脉闭塞脑缺血模型,随机分为NBO组和对照组,每组8只。分别于2 h和24 h行头颅MRI扫描。冠状位DWI测量大鼠的脑梗死体积及增大率;在脑梗死最大层面的表观扩散系数(ADC)图上测量脑梗死中心区和边缘区的ADC值,并计算ADC值的降低率。取脑行HE染色,并与DWI结果进行比较。结果 NBO组与对照组大鼠右侧大脑中动脉供血区异常高信号,ADC图上为低信号。NBO组大鼠2h和24 h脑梗死体积增大率均低于对照组,但差异无统计学意义(P>0.05)。NBO组大鼠2 h和24 h梗死中心区ADC值降低率与对照组差异无统计学意义(P>0.05);而NBO组梗死边缘区ADC值降低率明显小于对照组(P<0.01)。NBO组与对照组大鼠HE染色脑梗死灶与相应DWI层面差异无统计学意义(P>0.05)。结论 DWI显示NBO对大鼠脑缺血有保护作用。

Objective To investigate the neuroprotective effect of normobaric oxygen（NBO） in the stroke rat model using MR diffusion-weighted imaging（DWI）. Methods The right middle cerebral artery occlusion models were made from 16 male SD rats. SD rats were randomly divided into NBO and control group. Each group has 8 rats. Brain MRI was performed at 2 hour and 24 b after MCAO, respectively. The infarction volume and the increased rate of infarction on DWI were compared between two groups. The value of apparent diffusion coefficient（ADC） of the infarction center and edge region and the decreased rate of ADC were also compared between two groups. HE stainings were performed and compared with DWI. Results Abnormal hyperintensity was found in the right cerebral ischemic region in NBO and control group. The infarction demonstrated low signal on ADC map. The increased rate of infraeted volume in NBO group was lower than control group after 2 and 24 hours,respectively. But there had no statistically significant differenee（P〉0. 05）. There had also no significant difference of the decreased rate of ADC values in infarction center after 2 and 24 hours between NBO and control group（P〉0.05）. However,the decreased rate of ADC values in infarction edge of NBO group was significantly lower than control group after 2 and 24 hours（P〈0.01）. There had no statistically significant difference of the infarction volumes between HE staining and DWI in NBO and control group（P〉0.05）. Conclusion DWI demonstrated that NBO has the neuroprotective effect on acute cerebral ischemia.