title: Skin organ culture as a model to study oxidative stress, inflammation and structural alterations associated with UVB-induced photodamage.
abstract: BACKGROUND
  Ultraviolet (UV) irradiation is a major cause of skin damage, of long-term alteration of skin metabolism, homoeostasis and physical structure. The analysis of UV-induced pathogenic processes requires in vitro models allowing biochemical studies, and appropriate for the development of novel, accurate diagnosis methods based on non-invasive procedures.
  
  
  OBJECTIVE
  This work was aimed to reproduce the effects of UVB on whole-skin explants ex vivo and to study underlying biochemical mechanisms, especially in correlation with skin autofluorescence.
  
  
  METHODS
  Human skin organ cultures were irradiated with UVB and subjected to enzyme assays, Western blots, solid-phase ELISA, HPLC and fluorescence measurements.
  
  
  RESULTS
  UVB irradiation was found to enhance ROS production, to deplete the pool of low-molecular-weight antioxidants and to decrease the overall antioxidant capacity in the epidermis, in a manner dependent on xanthine-oxidase activity. Epidermal cell proliferation and mitochondrial activity were transiently stimulated. IκB-α was degraded, and the secretion of inflammatory cytokines was drastically increased. Inducible nitric oxide synthase activity was increased in non-irradiated controls, probably due to the mechanical stress of skin excision, and this phenomenon was suppressed by UVB. Autofluorescence measurements revealed alterations of dermal protein crosslinks following UVB irradiation.
  
  
  CONCLUSIONS
  Skin organ culture proved to be an integrated model appropriate for in vitro analysis of UVB biologic effects and their correlations, and for the study of non-invasive diagnostic methods in cellular and molecular terms.
authors.affiliation: Institute of Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Ein Karem, Jerusalem, Israel.
authors.forename: Meital
authors.initials: M
authors.lastname: Portugal-Cohen
authors.forename: Yoram
authors.initials: Y
authors.lastname: Soroka
authors.forename: Marina
authors.initials: M
authors.lastname: Frušić-Zlotkin
authors.forename: Lilian
authors.initials: L
authors.lastname: Verkhovsky
authors.forename: François Menahem
authors.initials: FM
authors.lastname: Brégégère
authors.forename: Rami
authors.initials: R
authors.lastname: Neuman
authors.forename: Ron
authors.initials: R
authors.lastname: Kohen
authors.forename: Yoram
authors.initials: Y
authors.lastname: Milner
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D005453:Fluorescence; D006801:Humans; D020672:I-kappa B Proteins; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D008954:Models, Biological; D000072000:NF-KappaB Inhibitor alpha; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D009924:Organ Culture Techniques; D018384:Oxidative Stress / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D012867:Skin / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D020672:I-kappa B Proteins; C000606204:NFKBIA protein, human; D017382:Reactive Oxygen Species; D000072000:NF-KappaB Inhibitor alpha; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; D014969:Xanthine Oxidase