Effect of vitamin D3 on leukocyte infiltration into the brain of C57/BL6 mice with experimental autoimmune encephalomyelitis

Background: Leukocyte infiltration into the central nervous system (CNS) in diseases like multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) have been implicated in subsequent disease pathogenesis and progression. It suggested that vitamin D3 (active form of vitamin D) ameliorates the symptoms of EAE when administered after the onset of clinical sings. The aim of this study was to understand the efficacy of vitamin D3 against EAE, we examined the effect of vitamin D3 on the leukocyte infiltration into the brain of male C57BL/6 mice with MOG35-55- induced EAE. Material and methods: Male C57BL/6 mice were divided into two therapeutic groups (n=8 per group) with age and weight-matched as follow: Vitamin D3-treated EAE mice (5μg/kg/every two days of vitamin D3 given i.p.) from day -3 until day +19 after disease induction. Non-treated EAE mice (EAE control) received vehicle alone with same schedule. In addition, 5 age and weight-matched male C57BL/6 mice served as normal (non-EAE) controls. Results: Vitamin D3-treated mice had significantly less clinical score of EAE (3.2±0.8) than non-treated mice (5.3±0.44), (p<0.001). Also, there was a significant difference between vitamin D3-trated and non treated mice (p<0.01) in relation to the number of the infiltrating cells in the brain. Conclusion: These results indicate that vitamin D3 treatment reduces infiltration of leukocytes into the brain of EAE mice, and ameliorate the disease. Thus, vitamin D3 treatment may be of therapeutic value against inflammatory disease processes associated with infiltration of activated mononuclear cells into the tissue.