Antioxidant enzyme suppression of demyelination in experimental optic neuritis.

Detoxification of hydrogen peroxide by the antioxidant enzyme catalase suppressed the neurologic manifestations of acute experimental allergic encephalomyelitis (EAE) and prevented death of treated adult strain-13 guinea pigs. The oxygen radical scavenger superoxide dismutase (SOD) delayed the onset of paralysis by one day, but did not prevent death from encephalomyelitis common to most of this group and all untreated animals. Histopathologic analysis of the optic nerves confirmed a statistically significant reduction in demyelination with catalase treatment, but not with SOD. Hydrogen peroxide, and/or its conversion products, discharged by phagocytic mononuclear cells, may play a role in the pathogenesis of demyelination in experimental optic neuritis.