Vitamin D and sunlight have each been reported to protect against the development of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS). To date, the contribution of each has been unclear as ultra violet (UV) exposure also causes the generation of vitamin D in the skin. To examine whether the UV based suppression of EAE results, at least, in part from the production of vitamin D, we studied the effect of UV light on EAE in mice unable to produce 7-dehydroxycholesterol (7-DHC), the required precursor of vitamin D. Furthermore, we examined UV suppression of EAE in mice devoid of the vitamin D receptor (VDR). Our results demonstrate that UV light suppression of EAE occurs in the absence of vitamin D production and in the absence of VDR. Future investigations will focus on identifying the pathway responsible for the protective action of UV in EAE and presumably human MS.
Keywords: UV light; experimental autoimmune encephalomyelitis; vitamin D receptor.