EFFECT OF MUSCULAR EXERCISE ON CHRONIC RELAPSING EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS

We examined whether physical exercise affected the development of an a utoimmune response, experimental autoimmune encephalomyelitis (EAE), w hich is a demyelinating disease leading to paralysis. EAE was inducted on day 0, in rats of both sexes, by injecting them with spinal cord t issue in adjuvant. From clays 1 to 10 after injection, exercised rats (n = 55) ran on a treadmill (60-120 min/day) before the onset of the p aralytic disease. Clinical signs of the disease (ataxia, paralysis, an d body mass loss) were examined in exercised and control rats (n = 54) . Three types of EAE were induced: monophasic, acute, acid chronic rel apsing (CR)-EAE (3 bouts of disease, CR-EAE 1, 2, and 3, separated by remissions). Exercise significantly delayed the onset of CR-EAE 1 (P = 0.001) and the Ist day of maximum severity of CR-EAE 1 (P = 0.001) an d CR-EAE 2 (P = 0.002). Moreover, the duration of CR-EAE 1 was signifi cantly decreased in exercised rats compared with control rats (P = 0.0 04). The peak severity of the different types of EAE was not modified by exercise. The present study indicates that endurance exercise durin g the phase of induction of EAE diminished lightly only one type of EA E (CR-EAE) and therefore did not exacerbate the autoimmune disease.