Suppression of multiple sclerosis in the rat during infection with Trichinella pseudospiralis.

Injection of the rat with guinea pig myelin basic protein (MBP) induces an inflammatory demyelination that leads to development of a condition mimicking human multiple sclerosis (MS), including severe depressions in mobility, coordination, and strength in the affected animal. This model was used to observe and compare the antiinflammatory effects of the intestinal and late migratory phases of infection with Trichinella pseudospiralis on development of MBP-induced, MS-like debilitation in rats. Animal performance was measured in an activity monitor and in a series of physical tests designed to assess animal coordination and strength. Uninfected animals injected with MBP showed declines in mobility, coordination, and strength typical for this model. These changes were similar in rats infected so that the intestinal phase of infection coincided with the peak of MBP-induced debilitation. Rats infected so that the late migratory phase of infection occurred during the period of peak MBP-induced debilitation showed significantly higher performance scores in mobility, coordination and strength compared to the latter 2 groups. These finding demonstrate the potency of the anti-inflammatory effects of elevations in host corticosteroids seen during the migratory phase of infection with T. pseudospiralis.