Time-course study of different innate immune mediators produced by UV-irradiated skin: comparative effects of short and daily versus a single harmful UV exposure

ELIANA M. CELA; ADRIAN FRIEDRICH; MARIELA L. PAZ; SILVIA I. VANZULLI; JULIANA LEONI; DANIEL H. GONZALEZ MAGLIO

IMMUNOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 145 p. 82 - 93

0019-2805

SummaryThe modulatory effects of solar UV radiation on the immune system havebeen widely studied. As the skin is the main target of UV radiation, ourpurpose was to compare the impact on skin innate immunity of two contrastingways to be exposed to sunlight. Hairless mice were UV irradiatedwith a single high UV dose simulating a harmful exposure, or with repetitivelow UV doses simulating short occasional daily exposures. Skin sampleswere taken at different times after UV irradiation to evaluate skinhistology, inflammatory cell recruitment, epidermal T-cell population andthe mitochondrial function of epidermal cells. The transcriptional profilesof pro-inflammatory cytokines, chemokines, antimicrobial peptides andToll-like receptors were evaluated by RT-PCR and ELISA in tissue homogenates.Finally, a lymphangiography was performed to assess modificationin the lymphatic vessel system. A single high UV dose produces adeep inflammatory state characterized by the production of pro-inflammatorycytokines and chemokines that, in turn, induces the recruitment ofneutrophils and macrophages into the irradiated area. On the other hand,repetitive low UV doses drive the skin to a photo-induced alert state inwhich there is no sign of inflammation, but the epithelium undergoeschanges in thickness, the lymphatic circulation increases, and the transcriptionof antimicrobial peptides is induced.