大鼠创伤性轴索损伤后脑代谢质子磁共振波谱分析

目的 使用质子磁共振波谱(1H-MRS)研究大鼠创伤性轴索损伤(traumatic axonal injury,TAI)后组织代谢改变及其空间分布特征.方法 使大鼠头颅发生线加速和角加速运动制作TAI模型.于伤前和伤后24 h采用多体素MRS方法检测大鼠脑内多个部位的组织代谢状态,分析伤后N-乙酰门冬氨酸(NAA)/总肌酸(Cr)、NAA/胆碱类化合物(Cho)和Cho/Cr值变化及NAA/Cr值变化的空间分布特征.采用免疫组化标记β淀粉样蛋白前体蛋白(β-APP)观察轴索损伤情况.结果 与伤前相比,伤后24 h时NAA/Cr、NAA/Cho值显著下降(P<0.05).Cho/Cr值轻度升高(P>0.05);NAA/Cr值出现较大降低幅度的部位依次为脑干、海马、内囊、胼胝体和丘脑.病理学检查示这些部位出现轴索损伤.结论 TAI后脑组织出现严重代谢紊乱,以脑干、海马等部位变化最为显著.

Abstract：

Objective To investigate the brain metabolic changes and evaluate their spatial distributions after traumatic axonal injury (TAI)in rats by using proton magnetic resonance spectroscopy(1H-MRS).Methods The TAI model was made by subjecting the head of the rats to the linear and angular accelerations.The multi-voxel MRS was employed to detect the tissue metabolic state at the levels of hippocampus-caudate and pons prior to injury and at 24 hours after injury.The alterations of NAA/Cr,NAA/Cho and Cho/Cr values as well as the spatial distribution of NAA/Cr reduction were accessed. Immunohistochemical staining for β-APP was used to observe the injured axons. Results A siguificantdecrease in NAA/Cr and NAA/Cho(P<0.05)and subtle increase in Cho/Cr(P>0.05)were observed in rats at 24 hours after TAI in comparison to the pre-injury levels.Notable decrease in NAA/Cr value was observed in the areas including the brain stem,hippocampus,internal capsule,corpus callosum and thalamus,where axonal injuries were confirmed by the histological examination. Conclusion Metabolic imbalances Occur in the brains of rats with TAI.with notable changes in the brain stem and the hippocampus.

Proton magnetic resonance spectroscopy of brain metabolism after traumatic axonal injury in rats

Objective To investigate the brain metabolic changes and evaluate their spatial distributions after traumatic axonal injury (TAI)in rats by using proton magnetic resonance spectroscopy(1H-MRS).Methods The TAI model was made by subjecting the head of the rats to the linear and angular accelerations.The multi-voxel MRS was employed to detect the tissue metabolic state at the levels of hippocampus-caudate and pons prior to injury and at 24 hours after injury.The alterations of NAA/Cr,NAA/Cho and Cho/Cr values as well as the spatial distribution of NAA/Cr reduction were accessed. Immunohistochemical staining for β-APP was used to observe the injured axons. Results A siguificantdecrease in NAA/Cr and NAA/Cho(P<0.05)and subtle increase in Cho/Cr(P>0.05)were observed in rats at 24 hours after TAI in comparison to the pre-injury levels.Notable decrease in NAA/Cr value was observed in the areas including the brain stem,hippocampus,internal capsule,corpus callosum and thalamus,where axonal injuries were confirmed by the histological examination. Conclusion Metabolic imbalances Occur in the brains of rats with TAI.with notable changes in the brain stem and the hippocampus.