title: Free radicals induced by sunlight in different spectral regions - in vivo versus ex vivo study.
abstract: Sunlight represents an exogenous factor stimulating formation of free radicals which can induce cell damage. To assess the effect of the different spectral solar regions on the development of free radicals in skin, in vivo electron paramagnetic resonance (EPR) investigations with human volunteers and ex vivo studies on excised human and porcine skin were carried out. For all skin probes, the ultraviolet (UV) spectral region stimulates the most intensive radical formation, followed by the visible (VIS) and the near infrared (NIR) regions. A comparison between the different skin models shows that for UV light, the fastest and highest production of free radicals could be detected in vivo, followed by excised porcine and human skin. The same distribution pattern was found for the VIS/NIR spectral regions, whereby the differences in radical formation between in vivo and ex vivo were less pronounced. An analysis of lipid composition in vivo before and after exposure to UV light clearly showed modifications in several skin lipid components; a decrease of ceramide subclass [AP2] and an increase of ceramide subclass [NP2], sodium cholesterol sulphate and squalene (SQ) were detectable. In contrast, VIS/NIR irradiation led to an increase of ceramides [AP2] and SCS, and a decrease of SQ. These results, which are largely comparable for the different skin models investigated in vivo and ex vivo, indicate that radiation exposure in different spectral regions strongly influences radical production in skin and also results in changes in skin lipid composition, which is essential for barrier function.
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Silke B
authors.initials: SB
authors.lastname: Lohan
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Müller
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Albrecht
authors.affiliation: Institute of Food Chemistry, Hamburg School of Food Science, University of Hamburg, Hamburg, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Mink
authors.affiliation: Institute of Food Chemistry, Hamburg School of Food Science, University of Hamburg, Hamburg, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Tscherch
authors.affiliation: Department of Gynecology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Fakher
authors.initials: F
authors.lastname: Ismaeel
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Lademann
authors.affiliation: Institute of Food Chemistry, Hamburg School of Food Science, University of Hamburg, Hamburg, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Rohn
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Martina C
authors.initials: MC
authors.lastname: Meinke
mesh_terms: D000368:Aged; D000818:Animals; D005260:Female; D005609:Free Radicals / Q000378:metabolism*; D064368:Healthy Volunteers; D006801:Humans; D050356:Lipid Metabolism / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000378:metabolism / Q000528:radiation effects*; D013552:Swine
chemical_list: D005609:Free Radicals
keywords: electron paramagnetic resonance spectroscopy; free radicals; oxidative stress; skin lipids; solar spectrum