Alteration of superoxide dismutase activity in the anterior horn in motoneuron disease patients.

Studies on anterior horn dissected from MND patients have demonstrated that MnSOD activity is increased when expressed as a percentage of total SOD activity when compared to controls. Total SOD activity (mean +/- SD) in controls = 414 +/- 105 U mg-1 tissue and in MND patients = 373 +/- 115 U mg-1 tissue, whereas CuZnSOD activity was higher in controls (290 +/- 91 U mg-1 tissue) than in MND patients (197 +/- 81 U mg-1 tissue). The reduction in CuZnSOD was compensated for by a concomitant elevation of MnSOD activity (control = 123 +/- 40.5 U mg-1 tissue, MND patients = 175 +/- 47 U mg-1 tissue). These data not only show an important deficit in anterior horn cell body protection against free radical-mediated cell damage, but are also are the first measurements of SOD isoenzymes in anterior horn neurones.