胞二磷胆碱对大鼠脑缺血后脑内水分子弥散与氢谱的影响

目的观察大鼠脑缺血后脑内组织水分子表观弥散系数(apparent diffusion coefficient, ADC)及乳酸(lactate, Lac)和 N-乙酰基天门冬氨酸(N-acetyl-aspartate, NAA) 的改变,以及胞二磷胆碱对它们的影响.方法 Wistar大鼠右侧大脑中动脉栓塞制作永久性脑缺血模型,将磁共振弥散加权成像(diffusion weighted imaging, DWI)异常的区域为 1H磁共振波谱分析(proton magnetic resonance spectroscopy, 1H MRS)定位.结果脑缺血组脑缺血6 h后患侧Lac升高,24 h达高峰,3 d时开始降低;而NA A于脑缺血6 h即有降低,24 h降到最低,3 d后开始升高,7 d时接近正常水平,各时间点 Lac值和NAA值与对照组相比有显著性差异(P<0.05).对照组和假手术胞二磷胆碱组无Lac产生,胞二磷胆碱对NAA及ADC值无明显影响.胞二磷胆碱组患侧与健侧的表观弥散系数比率[apparent diffusion coefficient ratio, ADCR (ADCR=患侧表观弥散系数/健侧表观弥散系数)]及患侧ADC值较脑缺血组明显增加(P<0.05),胞二磷胆碱治疗后患侧Lac逐渐降低(P<0.05)以及NAA逐渐升高(P<0.05).结论 1H MRS 能够反映动物脑缺血后脑内代谢物的改变.胞二磷胆碱能够改善脑缺血后代谢物的变化并减轻脑水肿形成.

Effects of citicoline on apparent diffusion coefficient of water molecules in brain tissue and changes of lactate and N-acetyl aspartate after cerebral ischemia in rats

Objective To study the effects of citicoline on the apparent diffusion coefficient (ADC) of the water molecules in the brain tissue and changes of lactate (Lac) and N-acetyl aspartate (NAA) after cerebral ischemia in rats. Methods The cerebral ischemic model was established in Wistar rats with the occlusion of the right middle cerebral artery. The abnormal region in diffusion weighted imaging (WDI) was analyzed with proton magnetic resonance spectroscopy ( 1H-MRS). Results The increase of Lac began in the 6 th hour after cerebral ischemia and came up to the highest level in the 24 th hour. Lac content was gradually decreased on the 3 rd day after ischemia. The decrease of NAA began in the 6 th hour after the occlusion of the artery, maximal decrease was found in the 24 th hour and it began to increase on the 3 rd day and came to nearly normal level on the 7 th day. Significant difference of Lac and NAA levels was found between the cerebral ischemia group and the control at all the time points (P<0.05). In the control and the sham-operation citicoline groups, no production of Lac was seen. Citicoline exerted no effects on the level of NAA and ADC. The ADC ratio (ADC of the ischemic hemisphere/ADC of the normal hemisphere) and the level of ADC were significantly higher in the citicoline group than in the ischemic group (P<0.05). The level of Lac was decreased gradually and that of NAA gradually increased after intraperitoneal injection of citicoline at all the time points (P<0.05). Conclusion Diffusion weighted imaging and proton magnetic resonance spectroscopy can determine the changes of ADC and metabolites after cerebral ischemia. The administration of citicoline is able to ameliorate the metabolic abnormality and the occurrence of cerebral edema.