In Vivo 31P-Nuclear Magnetic Resonance Studies on Energy Metabolism of Ischemic Gerbil Brain: Comparison between Unilateral and Bilateral Common Carotid Artery Occlusion Models

The changes of cerebral energy state under bilateral and unilateral common carotid artery occlusion-reflow models in Mongolian gerbils were studied using in vivo 31 P nuclear magnetic resonance spectrometry (3IP-MRS). All ten gerbils used in the bilateral common carotid artery occlusion-reflow model showed relatively uniform ischemic patterns, i.e., depletion of phosphocreatine (PCr) and adenosine triphosphate (ATP) and increase of inorganic phosphate (Pi) followed by relatively uniform recovery pattern of PCr, ATP and Pi. Among 20 gerbils used in the unilateral common carotid artery occlusion-reflow model, 6 animals displayed the ischemic pattern but 14 animals showed no significant changes during ischemia. The ischemic pattern recovered more rapidly in the unilateral ischemic group than in the bilateral one. Although the Mongolian gerbil has used customarily in the study of brain ischemia, the unilateral common carotid artery occlusion model showed significant interindividual variation concerning the change of brain energy state during ischemia. While the results of this study are essentially predictable from the prior works using classic biochemical methods, they are useful in the sense that we demonstrate the complete time course of changes in metabolites in the same animal.