P-31 MAGNETIC-RESONANCE SPECTROSCOPY STUDIES OF PIG SPINAL-CORD INJURY - MYELIN CHANGES, INTRACELLULAR PH, AND BIOENERGETICS

RATIONALE AND OBJECTIVES. Phosphorus-31 (P-31) nuclear magnetic resona nce (NMR) spectroscopy was used to monitor changes in phosphocreatine (PCr), adenosine triphosphate (ATP), inorganic phosphate (Pi), intrace llular pH (pH(i)), and free magnesium in the in vivo pig spinal cord a fter injury. METHODS. Phosphorus-31 NMR spectra were acquired from hea lthy (n = 4) and injured pig spinal cords (n = 8) under in vivo condit ions using a 4.7-tesla spectrometer, Spinal cords were injured by drop ping a 20-g weight from 20 cm onto the surgically exposed cord surface . RESULTS. In vivo spectra of injured cords revealed a reduction in AT P, PCr, pH(i), and an increase in Pi. In addition, a broad resonance t hat is likely to arise from myelin phospholipids was reduced significa ntly after injury. CONCLUSIONS. Phosphorus-31 NMR can be used to follo w in vivo changes in high energy phosphates after injury and may have the potential to follow changes in myelin structure, This technique ma y prove important in the study of myelin breakdown after secondary, no nreversible spinal cord injury, Changes in high energy phosphates and pH(i) did not seem to parallel these putative changes in myelin struct ure.