UV improves immune system without increasing vitamin D levels in male mice – Sept 2012

Acute Erythemal Ultraviolet Radiation Causes Systemic Immunosuppression in the Absence of Increased 25-Hydroxyvitamin D(3) Levels in Male Mice.

PLoS One. 2012;7(9):e46006. Epub 2012 Sep 26.
Gorman S, Scott NM, Tan DH, Weeden CE, Tuckey RC, Bisley JL, Grimbaldeston MA, Hart PH.
Telethon Institute for Child Health Research and Centre for Child Health Research, University of Western Australia, Perth, Western Australia, Australia.

Vitamin D is synthesised by ultraviolet (UV) irradiation of skin and is hypothesized to be a direct mediator of the immunosuppression that occurs following UV radiation (UVR) exposure. Both UVR and vitamin D drive immune responses towards tolerance by ultimately increasing the suppressive activities of regulatory T cells. To examine a role for UVR-induced vitamin D, vitamin D(3)-deficient mice were established by dietary vitamin D(3) restriction. In comparison to vitamin D(3)-replete mice, vitamin D(3)-deficient mice had significantly reduced serum levels of 25-hydroxyvitamin D(3) OH)D(3), <20 nmol.L(-1 and 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3), <20 pmol.L(-1)). Following either acute erythemal UVR, or chronic sub-erythemal UVR (8 exposures over 4 weeks) treatment, serum 25(OH)D(3) levels significantly increased in vitamin D(3)-deficient female but not male mice.

To determine if UVR-induced vitamin D was a mediator of UVR-induced systemic immunosuppression, responses were measured in mice that were able (female) or unable (male) to increase systemic levels of 25(OH)D(3) after UVR. Erythemal UVR (?4 kJ/m(2)) suppressed contact hypersensitivity responses (T helper type-1 or -17), aspects of allergic airway disease (T helper type-2) and also the in vivo priming capacity of bone marrow-derived dendritic cells to a similar degree in female and male vitamin D(3)-deficient mice. Thus, in male mice, UVR-induced 25(OH)D(3) is not essential for mediating the immunosuppressive effects of erythemal UVR.

PMID: 23049920

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Summary

1. Mice were given very little vitamin D in diets
2. UV radiation given to the mice improved their immune systems
3. UV only increased the vitamin D level in female mice
4. UV increased immune system in male mile without increasing vitamin D levels

See also VitaminDWiki

• Overview UV and vitamin D
• All items in category UV and vitamin D 381 items
• Perhaps more benefits from UV than just vitamin D - 2006
• UV produces more than vitamin D – Aug 2011
• Sun is better than UV, which is better than Vitamin D