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目的利用磁共振扩散加权成像(diffusion-weighted imaging,DWI)评价常压高浓度氧(normobaric oxygen,NBO)对急性脑缺血再灌注大鼠的保护作用。方法成年雄性SD大鼠16只,采用线栓法制作右侧大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)缺血模型,随机分为NBO组和对照组,每组8只,NBO组大鼠于MCAO模型后吸入常压氧气3 h。每组均在MCAO后2 h拔出线栓恢复脑组织血流灌注,MCAO后分别于30 min、6 h、24 h行头颅DWI。DWI上测量大鼠的脑梗死体积增长率及脑梗死中心区和边缘区的相对表观扩散系数(relative appar-ent diffusion coefficient,rADC)值。24 h后取脑行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均可见异常高信号,ADC图上表现为低信号。NBO组大鼠6 h和24 h脑梗死体积增长率均低于对照组(P<0.05)。6 h和24 h NBO组梗死病灶中心区rADC值与对照组差异无统计学意义(P>0.05);NBO组梗死病灶边缘区rADC值高于对照组(P<0.01)。NBO组和对照组大鼠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对显示NBO对急性脑缺血再灌注大鼠的保护作用有重要价值。
Objective To evaluate the protective effect of normobaric oxygen (NBO) on acute cerebral ischemia-reperfusion injury in rats by diffusion-weighted imaging (DWI). Methods Sixteen adult male Sprague-Dawley rats were randomly divided into NBO group and control group with 8 rats in each group. Rats in NBO group After the MCAO model inhaled atmospheric oxygen for 3 h. Each group was withdrawn at 2 h after MCAO to reperfusion the brain tissue perfusion, after MCAO 30min, 6h, 24h line head DWI. The volume growth rate of cerebral infarction and the relative appar-ent diffusion coefficient (rADC) values in the central and peripheral regions of cerebral infarction were measured on DWI. Twenty-four hours later, brain HE staining was performed and compared with DWI results. Results In the NBO group and the control group, abnormally high signal was observed in the right middle cerebral artery blood supply area and low signal was observed in the ADC image. The volume growth rates of cerebral infarction in NBO group at 6 and 24 h were all lower than those in control group (P <0.05). There was no significant difference in the rADC values between the infarct lesions in the NBO group and the control group at 6 h and 24 h (P> 0.05). The rADC values in the marginal zone of the NBO group were higher than those in the control group (P <0.01). NBO group and control group rats with HE staining cerebral infarction and the corresponding DWI level difference was not statistically significant (P> 0.05). Conclusion DWI is of great value to show the protective effect of NBO on acute cerebral ischemia-reperfusion in rats.