title: Effect of UVA fluence rate on indicators of oxidative stress in human dermal fibroblasts.
abstract: During the course of a day human skin is exposed to solar UV radiation that fluctuates in fluence rate within the UVA (290-315 nm) and UVB (315-400 nm) spectrum. Variables affecting the fluence rate reaching skin cells include differences in UVA and UVB penetrating ability, presence or absence of sunscreens, atmospheric conditions, and season and geographical location where the exposure occurs. Our study determined the effect of UVA fluence rate in solar-simulated (SSR) and tanning-bed radiation (TBR) on four indicators of oxidative stress---protein oxidation, glutathione, heme oxygenase-1, and reactive oxygen species--in human dermal fibroblasts after receiving equivalent UVA and UVB doses. Our results show that the higher UVA fluence rate in TBR increases the level of all four indicators of oxidative stress. In sequential exposures when cells are exposed first to SSR, the lower UVA fluence rate in SSR induces a protective response that protects against oxidative stress following a second exposure to a higher UVA fluence rate. Our studies underscore the important role of UVA fluence rate in determining how human skin cells respond to a given dose of radiation containing both UVA and UVB radiation.
authors.affiliation: Ferris State University, Department of Biological Sciences, Big Rapids, MI 49307 USA. hoerterj@ferris.edu
authors.forename: James D
authors.initials: JD
authors.lastname: Hoerter
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ward
authors.forename: Kyle D
authors.initials: KD
authors.lastname: Bale
authors.forename: Admasu N
authors.initials: AN
authors.lastname: Gizachew
authors.forename: Rachelle
authors.initials: R
authors.lastname: Graham
authors.forename: Jaclyn
authors.initials: J
authors.lastname: Reynolds
authors.forename: Melanie E
authors.initials: ME
authors.lastname: Ward
authors.forename: Chesca
authors.initials: C
authors.lastname: Choi
authors.forename: Jean-Leonard
authors.initials: JL
authors.lastname: Kagabo
authors.forename: Michael
authors.initials: M
authors.lastname: Sauer
authors.forename: Tara
authors.initials: T
authors.lastname: Kuipers
authors.forename: Timothy
authors.initials: T
authors.lastname: Hotchkiss
authors.forename: Nate
authors.initials: N
authors.lastname: Banner
authors.forename: Renee A
authors.initials: RA
authors.lastname: Chellson
authors.forename: Theresa
authors.initials: T
authors.lastname: Ohaeri
authors.forename: Langston
authors.initials: L
authors.lastname: Gant
authors.forename: Leah
authors.initials: L
authors.lastname: Vanderhill
mesh_terms: D002478:Cells, Cultured; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects; D005978:Glutathione / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D012867:Skin / Q000166:cytology / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D017382:Reactive Oxygen Species; D006419:Heme Oxygenase (Decyclizing); D005978:Glutathione