Changes in cerebral energy metobolism during chronic uasospasm in primates.

为了研究蛛网膜下腔出血（SAH）后慢性脑血管痉挛发展过程中脑循环损伤对神经元组织的影响，采用磷和质子磁共振波谱（MRS）方法，对灵长类动物血管痉挛模型慢性脑血管痉挛过程中脑能代谢和神经元代谢物的变化进行了评价。SAH是通过在右大脑中动脉（MCA）周围引入血凝块产生的。血管造影显示SAH诱导后第7天右侧大脑中动脉出现严重血管痉挛。磷MRS显示，药物性全身性低血压（平均60 mmHg）导致痉挛侧顶叶组织ATP水平在第7天显著降低。在SAH前，分别于第7天和第14天进行质子MRS。测定双侧顶叶含胆碱化合物（Cho）、肌酸和磷酸肌酸（Cr）和n -乙酰-天冬氨酸（NAA）的峰面积以及Cho/Cr和NAA/Cr的比值。质子磁共振成像显示，在第7天和第14天，痉挛侧右侧顶骨区NAA/Cr比值显著降低，Cho/Cr比值显著升高。组织病理学研究表明，痉挛动脉区域的部分皮质神经元（不到10%）发生缺血性神经元改变。结果提示，脑血管痉挛的发生导致血管痉挛动脉区域内的脑循环和能量代谢障碍，导致部分皮质神经元缺血性损伤。质子和/或磷核磁共振可用于评估脑血管痉挛期间缺血性损伤对神经元细胞的影响。

To study how neuronal tissues are affected by impairment of cerebral circulation during development of chronic cerebral vasospasm after subarachnoid hemorrhage (SAH), the changes in cerebral energy metabolism and neuronal metabolites during chronic cerebral vasospasm were evaluated by means of phosphorus and proton magnetic resonance spectrosopy (MRS), in a primate vasospasm model. The SAH was produced by introduction of blood clot around the right middle cerebral aretry (MCA). Angiography revealed severe vasospasm in the right middle cerebral artery on Day 7 after SAH induction. Phosphorus MRS revealed that drug-induced systemic hypotension (mean 60 mmHg) caused a significant decrease in the tissue ATP level in the spasm side parietal lobe on Day 7. Proton MRS was performed before SAH,on Day 7 and Day 14. The peak areas for choline-containing compounds (Cho), creatine and phosphocreatine (Cr) and N-acetyl-aspartate (NAA), and the ratios of Cho/Cr and NAA/Cr were evaluated in the bilateral parietal lobe. The proton MRS study revealed a significant reduction in NAA/Cr ratio on both Day 7 and Day 14, and a ignificant increase in Cho/Cr ratio, in the spasm side right parietal region. The histopathological study demonstrated the ischemic neuronal change in some (less than 10 %) of the cortical neurons in the territory of the spastic artery. The results suggest that the development of cerebral vasospasm caused impairment of cerebral circulation and energy metabolism in the territory of the vasospastic artery resulting in ischemic damage in some of the cortical neurons. The proton and/or phorphorus MRS may be useful to evaluate the effect of ischemic insult on neuronal cells during cerebral vasospasm.