广泛性焦虑大鼠前额叶皮质和海马磁共振波谱的研究

以广泛性焦虑大鼠为研究载体,探讨其前额叶皮质和海马组织质子磁共振波谱(1H-MRS)的变化及意义.大鼠分为正常组和模型组各8只,采用慢性情绪应激的方法建立广泛性焦虑大鼠模型,以国际公认的高架十字迷宫试验对其进行评价,在活体状态下,通过pharmascan70/16超导磁共振仪(7.0T)检测双侧海马及前额叶皮质N-乙酰天门冬氨酸(NAA)、胆碱(Cho)、谷氨酸(Glu)、肌酸(Cr)等代谢物水平,分别计算NAA、Cho和Glu与Cr的比值,进而对脑组织代谢进行定性及定量分析.正常组与广泛性焦虑组双侧海马及左侧前额叶皮质代谢物无明显差异(P0.05),广泛性焦虑大鼠右侧前额叶皮质NAA、Cho相对浓度较正常组显著降低(P0.05),Glu相对浓度则明显升高(P0.05).慢性焦虑情绪的产生可能与右侧前额叶皮质兴奋性神经递质谷氨酸的浓度升高、神经元的损伤或数量减少及细胞内信号转导的异常有关.

Metabolic Changes in Prefrontal Cortex and Hippocampus of Rats with Generalized Anxiety Revealed by In Vivo 1H-MRS

Metabolic changes in bilateral prefrontal cortex and hippocampus of rats with generalized anxiety disorder were investigated by ¹H magnetic resonance spectroscopy (¹H-MRS) performed at 7.0 T. Male Wistar rats were randomized assigned into the control and model groups (n =8 each). Chronic emotional stress-induced anxiety was used as the generalized anxiety disorder model. Behavioral abnormalities in the model rats were assessed with the elevated plus-maze test. Levels of cerebral metabolites, including N-acetyl aspartate (NAA), choline (Cho), creatine (Cr) and glutamate (Glu), in bilateral prefrontal cortex and hippocampus were measured and used to calculate NAA/Cr, Cho/Cr and Glu/Cr ratios. No significant metabolic difference were found between the model rats and the control rats in bilateral hippocampus and left prefrontal cortex. However, the model rats were found to have significantly lower NAA/Cr and Cho/Cr and significantly increased Glu/Cr in right prefrontal cortex, relative to the control rat. It is concluded that chronic anxiety may be associated with imbalance of amino acid neurotransmitters, neuronal injury/loss and intracellular signal transduction abnormalities in the right prefrontal cortex.