title: Selenium protects primary human keratinocytes from apoptosis induced by exposure to ultraviolet radiation.
abstract: The generation of reactive oxygen species has been implicated in ultraviolet radiation (UVR)-induced skin damage. In mice, increasing dietary selenium intake protects skin from UVR-induced DNA damage and photocarcinogenesis. We sought to determine whether selenium supplementation could protect keratinocytes from apoptosis resulting from exposure to broadband (TL20W/12) UVR. Unirradiated cultures contained 6.5 +/- 1% apoptotic cells; the maximum percentage of apoptotic cells (34 +/- 5%) was seen 16 h after UVR of 600 J/m(2). Under these conditions cell death from necrosis was 15 +/- 2.5% of the total cells. A 24-h preincubation with sodium selenite (10 nm(-1) microm) or selenomethionine (50 nm(-1) microm) protected cultured human keratinocytes from UVR-induced apoptosis. In primary keratinocytes the greatest reduction in apoptosis was found with 100 nm of either selenium compound (71% reduction in the numbers of total apoptotic cells; P < 0.01). Supplementation with 100-200 nm selenite or selenomethionine prevented UVR-induced apoptosis, but did not decrease the levels of UVR-induced p53, as measured by Western blotting. Collectively, this data suggests that selenium prevents UVR-induced cell death by inhibiting p53-independent cell death pathways.
authors.affiliation: Department of Dermatology, University of Edinburgh, Scotland.
authors.forename: T S
authors.initials: TS
authors.lastname: Rafferty
authors.forename: G J
authors.initials: GJ
authors.lastname: Beckett
authors.forename: C
authors.initials: C
authors.lastname: Walker
authors.forename: Y C
authors.initials: YC
authors.lastname: Bisset
authors.forename: R C
authors.initials: RC
authors.lastname: McKenzie
mesh_terms: D000165:Acridine Orange; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D012643:Selenium / Q000494:pharmacology*; D012645:Selenomethionine / Q000494:pharmacology; D018038:Sodium Selenite / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D016159:Tumor Suppressor Protein p53; D012645:Selenomethionine; D000165:Acridine Orange; D012643:Selenium; D018038:Sodium Selenite