Chronic exercise confers neuroprotection in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disease that affects the CNS, resulting in accumulated loss of cognitive, sensory, and motor function. This study evaluates the neuropathological effects of voluntary exercise in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Two groups of C57BL/6J mice were injected with an emulsion containing myelin oligodendrocyte glycoprotein and then randomized to housing with a running wheel or a locked wheel. Exercising EAE mice exhibited a less severe neurological disease score and later onset of disease compared with sedentary EAE animals. Immune cell infiltration and demyelination in the ventral white matter tracts of the lumbar spinal cord were significantly reduced in the EAE exercise group compared with sedentary EAE animals. Neurofilament immunolabeling in the ventral pyramidal and extrapyramidal motor tracts displayed a more random distribution of axons and an apparent loss of smaller diameter axons, with a greater loss of fluorescence immunolabeling in the sedentary EAE animals. In lamina IX gray matter regions of the lumbar spinal cord, sedentary animals with EAE displayed a greater loss of α-motor neurons compared with EAE animals exposed to exercise. These findings provide evidence that voluntary exercise results in reduced and attenuated disability, reductions in autoimmune cell infiltration, and preservation of axons and motor neurons in the lumbar spinal cord of mice with EAE.