Proton nuclear magnetic resonance spectroscopy (NMRS) was performed to study metabolite alterations in the rabbit brain and spinal cord homogenates and cytosolic fractions by the 600 MHz spectroscope of Firenze and the 300 MHz spectroscope of Bratislava following ligation of abdominal aorta below the renal arteries and resulting paraplegia. In 13 rabbits the abdominal aorta was occluded at various time points (1, 2 and 3 hours). In 30 rabbits the abdominal aorta was occluded temporarily for 25 minutes and reopened for 1 hour, and 3 hours reperfusion. Seventeen rabbits were the control. The method of integrated absolute signal-intensity peak area ratio relative to NAA and to Cr was applied to study the metabolites detected in the high- field region. Decrease of NAA, and increase of Lac, Ala, Ac, GABA, NAAG, Glu, Asp, Cho, and Ino were observed all along the encephalomedullary axis with major alteration of the lower thoracic and upper lumbar spinal cord, which are closer to the aorta occlusion. However, temporary amelioration of the metabolite alteration during the first hour of reperfusion and worsening at the third hour of reperfusion were observed. It was speculated that the temporary amelioration could be caused by the defense mechanisms (scavengers, SOD, glutathione etc.) with the exhaustion after 1 hour. The temporary amelioration was also confirmed by histological examination. The present study and our previous report demonstrate the enormous potential of the NMRS in monitoring the metabolic alteration in the early stage of ischemia before the cell damage becomes irreversible. Although the signals of the metabolites reflect the in vitro and not the in vivo situation, the ischemia information obtained were quite relevant compared with the normal rabbit brain and spinal cord of control. This will facilitate the identification of the NMRS signals in vivo complicated by the difficulties of acquiring localized spectra from the long narrow organ deeply buried in a bony canal.
|Number of pages||22|
|Journal||Journal of Neurological and Orthopaedic Medicine and Surgery|
|Publication status||Published - 1994|
ASJC Scopus subject areas
- Clinical Neurology