OXIDATIVE DAMAGE TO MUSCLE PROTEIN IN DUCHENNE-MUSCULAR-DYSTROPHY

THE hypothesis that reactive free radical species (ROS) may contribute to the pathogenesis of Duchenne muscular dystrophy (DMD) has been sug gested previously, but experimental data obtained in support of the ab ove have to date proved inconclusive. The recent discovery that nitric oxide synthase (required for muscle relaxation) is associated with th e sarcolemmal protein dystrophin normally and that both proteins are a bsent in DMD has heightened interest in the potential role of ROS in t his disorder. We therefore investigated oxidative damage to proteins i n the quadriceps femoris muscle by quantifying protein carbonyl levels in six patients with DMD and six normal controls. In DMD, the mean pr otein carbonyl level in the quadriceps femoris muscle was increased by 211% (p < 0.005) compared with the normal control subjects. The data thus support the hypothesis for the role of ROS induced protein oxidat ion of muscle cell damage in DMD.