(R)-ketamine ameliorates the progression of experimental autoimmune encephalomyelitis in mice

Multiple sclerosis (MS) is an immune-mediated neurological disease that attacks the central nervous system, including spinal cord and brain. Experimental autoimmune encephalomyelitis (EAE) is the most commonly used model for MS. Depression is the most prevalent comorbidity in MS patients. We previously demonstrated that ( R )-ketamine would be a novel antidepressant without side effects of ketamine. This study was undertaken to investigate whether ( R )-ketamine could attenuate disease progression in EAE mouse model. ( R )-ketamine (10 mg/kg/day for 15 days) significantly attenuated the reduction of body weight in EAE model mice compared to saline-treated mice. Furthermore, ( R )-ketamine ameliorated the clinical EAE scores compared to saline-treated mice. Moreover, ( R )-ketamine significantly attenuated the marked increases in the pathological scores, microglial activation, and blood-brain barrier integrity in the spinal cord compared to saline-treated mice. In conclusion, the current study suggests that ( R )-ketamine could ameliorate EAE clinical scores and pathological changes in the spinal cord of EAE mice. Therefore, it is likely that ( R )-ketamine would be a new potential prophylactic drug for MS. ● ( R )-ketamine attenuated body weight reduction in EAE model mice. ● ( R )-ketamine ameliorated clinical EAE scores. ● ( R )-ketamine attenuated microglial activation of EAE mice. ● ( R )-ketamine attenuated blood-brain barrier integrity of EAE mice. ● ( R )-ketamine would be a new drug for multiple sclerosis.