Reduction of lower motor neuron degeneration in wobbler mice by N-acetylcysteine

Jeffrey T. Henderson, Mohammed Javaheri, Susan Kopko and John C. Roder

Samuel Lunenfeld Research Institute, Mount Sinai Hospital,
Program in Molecular Biology and Cancer, 600 University Ave., Toronto, Ontario M5G-1X5

Abstract

The murine mutant wobbler is a model of lower motor neuron degeneration with associated skeletal muscle atrophy. This mutation most closely resembles Werdnig-Hofmann disease in humans and shares some of the clinical features of amyotrophic lateral sclerosis (ALS). It has been suggested that reactive oxygen species (ROS) may play a role in the pathogenesis of disorders such as ALS. In order to examine the relationship between ROS and neural degeneration, we have studied the effects of agents such as N-acetylcysteine (NAC), which reduce free radical damage. Litters of wobbler mice were given a solution of one percent solution of the glutathione precursor NAC in their drinking water for a period of nine weeks. Functional and neuro-anatomical examination of these animals revealed that wobbler mice which NAC exhibited: (1) a significant reduction in motor neuron loss and elevated glutathione peroxidase levels within the cervical spinal cord; (2) increased axon caliber in the medial facial nerve; (3) increased muscle mass and muscle fiber area in the triceps, and flexor carpi ulnaris muscles and; (4) increased functional efficiency of the forelimbs compared to untreated wobbler littermates. These data suggest that reactive oxygen species may be involved in the degeneration of motor neurons in wobbler mice; and demonstrate that oral administration of NAC effectively reduces the degree of motor degeneration in wobbler mice. This treatment may thus be applicable in the treatment of other lower motor neuropathies.

Space filling model of N-acetyl-L-cysteine

Introduction

Materials and Methods

Results

Discussion

References