A P-31-MAGNETIC RESONANCE SPECTROSCOPY AND BIOCHEMICAL-STUDY OF THE MO(VBR) MOUSE - POTENTIAL MODEL FOR THE MITOCHONDRIAL ENCEPHALOMYOPATHIES

P-31-magnetic resonance spectroscopy (P-31-MRS) provides new biochemic al information on mitochondrial disorders affecting brain and muscle. To elucidate the mechanisms of mitochondrial abnormalities, however, a nimal models are needed, We assessed the mo(vbr) (mottled viable brind led) mouse for its value in studying (1) energetics of a mitochondrial disorder and (2) P-31-MRS changes associated with mitochondrial abnor malities in vivo. The maximal activity of succinate-cytochrome c reduc tase was significantly reduced in mo(vbr) muscle compared to controls, whereas cytochrome oxidase activity was only reduced in mo(vbr) brain , P-31-MRS of mo(vbr) brain showed an increased pH, but no changes in any metabolite ratios. The phosphocreatine (PCr) recovery rate after e xercise was reduced in muscles from mo(vbr) mice, indicating impairmen t of oxidative metabolism. We conclude that mo(vbr) brain and muscle t issue have biochemical abnormalities consistent with mitochondrial imp airment. The PCr recovery rate, measured by P-31-MRS, was sensitive to the muscle abnormality, This strain is best described as having chron ic mitochondrial dysfunction. (C) 1997 John Wiley & Sons, Inc.