Feasibility of Deuterium Metabolic Magnetic Resonance Spectroscopy for the Investigation of Ischemia and Reperfusion in Rat Brain Slices Perfused Ex Vivo

Investigating glucose metabolism in the brain using [6,6-²H₂]glucose (²H₂-Glc) and deuterium-based NMR spectroscopy has shown promise for noninvasive monitoring of the fate of this labeled compound. This approach has already been applied in vivo in small animals and human subjects. A model of perfused rat brain slices recently showed promise for the investigation of the metabolic consequences of acute ischemic stroke, which is a significant cause of death and morbidity worldwide. The current study aimed to implement the deuterium-based glucose metabolism monitoring approach to study the metabolic consequences of ischemia and reperfusion in the rat brain ex vivo. In agreement with previous studies, we found that deuterated lactate (²H₂-Lac) was immediately formed in the brain upon administration of ²H₂-Glc to the perfusion medium. This metabolite remained the predominant metabolic fate observed in the ²H-NMR spectra. Upon perfusion arrest, ²H₂-Lac quickly built up to the same amount of ²H₂-Glc eliminated from the medium engulfing the slices, reaching fivefold to sixfold its baseline level (n = 6, three animals, and two ischemic conditions in each). Upon reperfusion, ²H₂-Lac decreased to its level before the ischemic condition, and ²H₂-Glc returned to its baseline. ²H₂-Lac washout to the medium amounted to 2.2% of the ²H₂-Lac signal associated with the slices after about 5 h of perfusion with ²H₂-Glc, suggesting that the ²H₂-Lac signal observed during the experiments was predominantly intracellular. These results demonstrate the utility of ²H₂-Glc and ²H-NMR in monitoring the consequences of ischemia and reperfusion in the perfused rat brain slices model.