Spermidine alleviates severity of murine experimental autoimmune encephalomyelitis.

PURPOSE To assess the effects of spermidine on the severity of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), with a focus on optic neuritis often associated with MS and EAE. METHODS Myelin oligodendrocyte glycoprotein-induced EAE mice were administered with or without spermidine at 30 mM in drinking water for 25 days. Clinical signs of EAE were scored daily, and visual functions were measured by multifocal electroretinograms. Histopathology analysis of the spinal cord and optic nerve was performed after mice were killed on day 25. Hydrogen peroxide (H(2)O(2)) was detected using the probe 2'-7' dichlorofluorescein diacetate (DCFDA) in the optic nerve. The effect of spermidine on H(2)O(2)-induced retinal ganglion cell apoptosis was investigated by lactate dehydrogenase assay. RESULTS Daily clinical scoring revealed that the severity of EAE was significantly attenuated in the spermidine-treated group, which was confirmed by milder demyelination and improved axon survival in the spinal cord of spermidine-treated mice. Visual functions were significantly improved in spermidine-treated mice compared with vehicle-treated mice. Spermidine treatment ameliorated the extent of demyelination in the optic nerve and prevented cell loss in the retinal ganglion cell layer. Furthermore, fewer DCFDA-labeled cells were found in the optic nerve in the spermidine-treated EAE mice, and in vitro analysis revealed that spermidine reduced H(2)O(2)-induced retinal ganglion cell apoptosis, suggesting that spermidine alleviated the severities of EAE, particularly of optic neuritis, by acting as an antioxidant. CONCLUSIONS The results from this study suggest that oral spermidine administration could be a useful treatment for MS.