title: UVB irradiation-induced impairment of keratinocytes and adaptive responses to oxidative stress.
abstract: UVB irradiation of human skin is known to induce pathophysiological processes as oxidative stress and inflammation. HaCaT keratinocytes represent a well-established in vitro model system to investigate the influence of UVB irradiation on cell cultures. It was the aim of these investigations to study the effects of moderate UVB doses on cellular and mitochondrial integrity of HaCaT keratinocytes, biomarkers of oxidative stress and antioxidant protection by superoxide dismutases. F(2)-isoprostane concentrations were UVB dose-dependently enhanced reaching a plateau at 50 mJ/cm(2). Cell viability was reduced and apoptosis was enhanced with increasing UVB doses. The activities of the respiratory chain complexes were practically not altered at lower UVB doses, up to 50 mJ/cm(2), whereas remarkable decreases, also for the levels of cardiolipin species, were seen at 100 mJ/cm(2). As an adaptive response to the enhanced oxidative stress, protein levels of MnSOD increased about 3-fold at 50 mJ/cm(2) and decreased at higher doses. From the data it can be concluded that keratinocytes are sufficiently protected at low UVB doses, whereas higher doses lead to irreversible cell damage.
authors.affiliation: Department of Pathological Biochemistry, Institute of Clinical Chemistry and Pathological Biochemistry, Germany. ingrid.wiswedel@medizin.uni-magdeburg.de
authors.forename: Ingrid
authors.initials: I
authors.lastname: Wiswedel
authors.forename: Gerburg
authors.initials: G
authors.lastname: Keilhoff
authors.forename: Lena
authors.initials: L
authors.lastname: Dörner
authors.forename: Ana
authors.initials: A
authors.lastname: Navarro
authors.forename: Raik
authors.initials: R
authors.lastname: Böckelmann
authors.forename: Bernd
authors.initials: B
authors.lastname: Bonnekoh
authors.forename: Andreas
authors.initials: A
authors.lastname: Gardemann
authors.forename: Harald
authors.initials: H
authors.lastname: Gollnick
mesh_terms: D000222:Adaptation, Physiological; D017209:Apoptosis; D002308:Cardiolipins / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D003872:Dermatitis / Q000209:etiology / Q000473:pathology; D004579:Electron Transport; D006801:Humans; D015603:Keratinocytes / Q000201:enzymology / Q000473:pathology / Q000528:radiation effects*; D008928:Mitochondria / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D002308:Cardiolipins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase