Tumor necrosis factor is increased in the spinal cord of an animal model of motor neuron degeneration.

Autoimmunity and oxidative/excitotoxic damage are considered as possible pathogenetic mechanisms in amyotrophic lateral sclerosis (ALS). As tumor necrosis factor (TNF) is implicated in autoimmune diseases, including experimental autoimmune encephalomyelitis, and can be neurotoxic, we studied TNF production in a proposed animal model of ALS, the mnd mouse. These mice develop symptoms (progressive weakness of the limbs) as late as at 7 months of age. We measured TNF in serum, brain and spinal cord of mnd mice at 3 and 7 months of age. TNF was detectable in the brain and spinal cord (but not in the serum) at 7 months, while no TNF was detected in mnd mice at 3 months (asymptomatic) or in control mice of the same genetic background and the same age. Immunohistochemistry confirmed localization of TNF-alpha in motor neurons situated in the ventral horn of the spinal cord of 7-month old mnd mice. These results suggest the possibility of testing inhibitors of TNF production in this disease.