title: 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.
abstract: The modulatory effects of solar UV radiation on the immune system have been widely studied. As the skin is the main target of UV radiation, our purpose was to compare the impact on skin innate immunity of two contrasting ways to be exposed to sunlight. Hairless mice were UV irradiated with a single high UV dose simulating a harmful exposure, or with repetitive low UV doses simulating short occasional daily exposures. Skin samples were taken at different times after UV irradiation to evaluate skin histology, inflammatory cell recruitment, epidermal T-cell population and the mitochondrial function of epidermal cells. The transcriptional profiles of pro-inflammatory cytokines, chemokines, antimicrobial peptides and Toll-like receptors were evaluated by RT-PCR and ELISA in tissue homogenates. Finally, a lymphangiography was performed to assess modification in the lymphatic vessel system. A single high UV dose produces a deep inflammatory state characterized by the production of pro-inflammatory cytokines and chemokines that, in turn, induces the recruitment of neutrophils and macrophages into the irradiated area. On the other hand, repetitive low UV doses drive the skin to a photo-induced alert state in which there is no sign of inflammation, but the epithelium undergoes changes in thickness, the lymphatic circulation increases, and the transcription of antimicrobial peptides is induced.
authors.affiliation: Cátedra de Inmunología (Universidad de Buenos Aires) - Instituto de Estudios de la Inmunidad Humoral (IDEHU-CONICET), Buenos Aires, Argentina.
authors.forename: Eliana M
authors.initials: EM
authors.lastname: Cela
authors.forename: Adrian
authors.initials: A
authors.lastname: Friedrich
authors.forename: Mariela L
authors.initials: ML
authors.lastname: Paz
authors.forename: Silvia I
authors.initials: SI
authors.lastname: Vanzulli
authors.forename: Juliana
authors.initials: J
authors.lastname: Leoni
authors.forename: Daniel H
authors.initials: DH
authors.lastname: González Maglio
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000276:immunology; D018925:Chemokines / Q000276:immunology; D004307:Dose-Response Relationship, Radiation; D007113:Immunity, Innate / Q000528:radiation effects*; D018836:Inflammation Mediators / Q000276:immunology*; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D051379:Mice; D020556:Neutrophil Infiltration / Q000276:immunology / Q000528:radiation effects; D009504:Neutrophils / Q000276:immunology / Q000473:pathology; D012867:Skin / Q000276:immunology* / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D013997:Time Factors; D051193:Toll-Like Receptors / Q000276:immunology; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D023181:Antimicrobial Cationic Peptides; D018925:Chemokines; D018836:Inflammation Mediators; D051193:Toll-Like Receptors
keywords: chemotaxis; inflammation; photoadaptation; skin; ultraviolet radiation