C57BL/6 The Effect of Vitamin D3 on the Inhibition of Experimental Autoimmune Encephalomyelitis in C57BL/6 Mice

Multiple sclerosis(MS) is a chronic autoimmune disease of unknown etiology affecting the central nervous system. The prevalence of MS is the highest where environmental supply of vitamin D is low. Some studies have shown a strong protective effect of vitamin D3 on experimental autoimmune encephalomyelitis(EAE) of MS model¡ but it is not known how it affects EAE. Vitamin D3 may inhibit EAE by affecting nitric oxide(NO) production. The present study was carried out to investigate the effect of vitamin D3 on the evolution of MOG35-55 induced EAE and level of nitric oxide in male C57BL/6 mice.
Male C57BL/6 mice with similar age and weight were placed in two therapeutic groups(n=8 per group) as follow: 1) Vitamin D3-treated EAE mice(5µg/kg/every two days of vitamin D3 given i.p from day -3 until day after disease induction)¡ 2) 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.
The results showed that vitamin D3-treated mice had significantly less clinical score of EAE(3.2±0.8) than non-treated EAE induced mice(5.3±0.44)¡ (P=0.001). Also¡ there was a significant difference on the day of onset of disease between vitamin D3-treated and non-treated EAE-induced mice(day 15±1 and day 11±1¡ respectively). NO concentration in vitamin D3-treated mice was significantly lower than EAE control(P=0.008).
By considering the role of NO in the pathogenesis of EAE and MS¡ it seems vitamin D3 has immune modulatory responses and can reduce or delay the onset of EAE by reducing NO production. Thus¡ vitamin D3 is potentially important for treatment of MS.