摘要
目的通过对比性研究大鼠在微波辐射后的功能磁共振影像技术(fMRI)获取的海马影像表征参数与空间记忆能力及海马脑区病理结构改变之间的关联性,探讨将fMRI应用于微波辐射脑损伤效应研究的可行性。方法以30 mW/cm^2的微波一次辐射27只Wistar雄性大鼠15 min,对照组24只,于辐射后6 h、1 d、2 d、3 d、4 d、7 d、14 d分别采用Morris水迷宫检测大鼠空间记忆能力改变;光镜和电镜观察海马脑区病理变化;并应用fMRI的扩散加权成像(DWI)、动脉自旋标记(ASL)和磁共振波谱(MRS)等技术动态扫描海马脑区的表观扩散系数(ADC)、血流灌注(CBF)、代谢物质等变化。结果微波辐射后1~3 d大鼠平均逃避潜伏期(AEL)显著延长(P<0.05或P<0.01);海马神经元出现变性、凋亡(核染色质凝聚、边集)、坏死;线粒体肿胀空化、血管周间隙增宽。fMRI扫描成像显示,辐射后3~14 d分别海马脑区ADC值升高,血流灌注(CBF)减少,MRS显示海马脑区代谢物质N-乙酰天门冬氨酸与肌酸的比值(NAA/Cr)、谷氨酸类化合物与肌酸的比值(Glx/Cr)显著增加,胆碱化合物与肌酸的比值(Cho/Cr)显著降低,上述海马区病变及行为认知障碍等损伤效应与fMRI显示的特征参数在辐射后1~7 d呈现明显的一致性。结论微波辐射致大鼠海马损伤的fMRI特征与其行为认知障碍、组织结构病变及生物代谢指标变化具有良好的关联性。
Objective To explore the correlation between the functional magnetic resonance imaging（fMRI） characteristics and the spatial memory ability and the pathological changes of hippocampus in rats after exposured under microwave radiation. To discuss the feasibility of fMRI in studying the microwave radiation injury. Methods 27 rats were irradiated by 30 mW/cm^2 microwave for 15 min,after that the radiation group were used to test spatial memory in Morris water maze（MWM）; hippocampus was observed pathological changes under optical microscope and transmission electron microscope; we chose DWI,ASL,MRS of fMRI scanning in the rats hippocampus to detect the changes of ADC,CBF and metabolic substances. Results 1 ~ 3 d after microwave exposure,the average escape latency（AEL） of rats was prolonged in MWM test. Degeneration and apoptosis（nuclear chromatin condensation and margination） and necrosis; mitochondria swelling and perivascular space widened can be observed in the hippocampus. 3 ~ 14 d after microwave exposure,fMRI imaging shows that ADC increased and CBF decreased; significant increases in NAA/Cr and Glx/Cr,but significant decreases in Cho/Cr in part of the hippocampus. A significant consistency between the pathological changes in hippocampus and cognitive impairment and the the changes of MRS especially in the 1 ~ 7 d. Conclusions It was found that the magnetic resonance imaging characteristics of hippocampus injury induced by microwave radiation were correlated with cognitive impairment,pathological changes of hippocampus and biological metabolism.
出处
《中国体视学与图像分析》
2017年第1期77-86,共10页
Chinese Journal of Stereology and Image Analysis
基金
国家自然科学基金面上项目(81472951)
关键词
微波辐射
大鼠
FMRI
海马
micowave
rat
functional magnetic resonance imaging（fMRI）
hippocampus
