摘要
目的利用MRI-DWI动态观察褪黑素(MT)对急性脑缺血再灌注(IR)大鼠的保护作用。方法将96只雄性Sprangue Dawley大鼠随机分为假手术组(分离血管后缝合,并于分离前30 min腹腔注入生理盐水)、模型组(造模前后30 min腹腔注射生理盐水)、MT组(造模前后30 min腹腔注射10 ml/kg MT),每组32只。采用改良Longa线栓法制作局灶性脑IR模型。于缺血2 h再灌注后6 h、24 h、72 h、7天行头颅T2WI、DWI扫描,测量脑梗死区的相对T2信号强度(r SI-T_2WI)、相对表观扩散系数(r ADC);HE染色观察组织病理形态改变。结果假手术组大鼠MRI未见异常信号,脑神经细胞排列密集,形态规则,间质无水肿。MT组与模型组大鼠T_2WI、DWI图均可见右侧大脑皮层及纹状体出现异常高信号,ADC图为低信号,脑梗死区r ADC值逐渐上升,而r SI-T2WI 24 h内逐渐上升,随后开始下降,脑梗死区神经细胞皱缩、溶解、坏死,间质水肿。MT组与模型组比较,脑梗死区r ADC值明显升高(P<0.05),r SI-T_2WI明显降低(P<0.05),脑水肿减轻,神经细胞凋亡数减少,形态较规则。结论 MT预处理能在一定程度上减轻大鼠IR后脑水肿及脑神经细胞损伤,MRI-DWI对评价MT的神经保护作用具有重要价值。
Objective To observe dynamically the neuroprotection of melatonin in acute cerebral ischemia reperfusion （IR） rats using MRI DWI. Methods Ninety six male Sprangue Dawley rats were divided randomly into sham group, model group, melatonin group, with 32 rats in each group. Modified Longa thread embolism method is used to establish the focal cerebral ischemia reperfusion model. Each group of rats were performed T2WI, DWI examination in 6hours, 24 hours, 72 hours, 7days respectively after 2 hours ischemia/reperfusion, to measure the relative T2 signal intensity （rSI T2WI） and apparent diffusion coefficient（rADC） in cerebral infarction area. After MRI scanning, rat brains were stained with hematoxylin eosin, to observe the histopathological morphologic change. Results There is no abnormal sign on T2 WI, DWI and ADC in sham group, the distribution of brain nerve cells was dense, the sharp was structured and there was no interstitial edema. Abnormal hyperintensity was found in the right brain cortex and striatum on T2WI and DWI in MT group and model group, low signal was found on ADC. The rADC increased gradually in cerebral infarction area, the rSl T2WI increased in 24 hours , and then declined, the brain nerve cells shrinked, dissolved and necrotized in cerebral infarction area, the surrounding interstitial edema compared with model group, the rADC of MT group rats in cerebral in- farction area increased significantly（ P 〈 0.05 ） , the rSI T2 WI of MT group rats decreased obviously（ P 〈 0.05 ） , the sur- rounding interstitial edema lighten, the number of poptotic brain nerve cells were less and The nerve cell morphology was more structured. Conclusion Melatonin can alleviate brain edema and the injury of brain nerve cells after cerebral ische- mia reperfusion to some degree, MRI DWI is important to evaluate the neuroprotective effect of melatonin.
出处
《临床放射学杂志》
CSCD
北大核心
2015年第12期1999-2003,共5页
Journal of Clinical Radiology
基金
国家自然科学基金项目(No：81000268)
山东省自然科学基金项目(No：2R2014JL049、2R2013HL067)
山东省医药卫生科技发展计划项目(No：2013WS0295)
关键词
脑缺血再灌注
扩散加权成像
磁共振成像
褪黑素
Cerebral isehemia-reperfusion Diffusion-weighted imaging Magnetic resonance imaging Melatonin
