title: Benzoyl peroxide increases UVA-induced plasma membrane damage and lipid oxidation in murine leukemia L1210 cells.
abstract: Ultraviolet A radiation induces oxidative stress and cell damage. The purpose of this investigation was to examine whether ultraviolet A-induced cell injury was amplified by the presence of a non-ultraviolet A absorbing molecule capable of generating free radicals. Benzoyl peroxide was used as a lipid soluble potential radical-generating agent. Plasma membrane permeability assessed by trypan blue uptake was used to measure cell damage in murine leukemia L1210 cells. Cells were irradiated with a pulsed Nd/YAG laser at 355 nm using 0-160 J per cm2. The ratio of the fluence-response slope in the presence of 40 microM benzoyl peroxide to that of irradiated controls was 4.3 +/- 2.6. Benzoyl peroxide alone or benzoyl peroxide added after irradiation did not cause increased trypan blue uptake. The ratio of the fluence-response slopes in the presence of 40 microM benzoyl peroxide to that of irradiated controls was 4.7 +/- 1.4 when cells were irradiated (0-43 J per cm2) with a xenon lamp, filtered to remove wavelengths <320 nm. The increased trypan blue uptake in 355 nm-irradiated cells in the presence of benzoyl peroxide was inhibited in a concentration-dependent manner by butylated hydroxytoluene, vitamin E, and trolox, a water-soluble vitamin E derivative. Lipid oxidation, assessed as thiobarbituric acid reactive substances, was significantly increased in samples irradiated with ultraviolet A in the presence of benzoyl peroxide at fluences >34 J per cm2. The increased trypan blue uptake and thiobarbituric acid reactive substances were inhibited by butylated hydroxytoluene. These results suggest that agents not absorbing ultraviolet A radiation may enhance ultraviolet A-initiated oxidative stress in cells.
authors.affiliation: Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Ibbotson
authors.forename: C R
authors.initials: CR
authors.lastname: Lambert
authors.forename: M N
authors.initials: MN
authors.lastname: Moran
authors.forename: M C
authors.initials: MC
authors.lastname: Lynch
authors.forename: I E
authors.initials: IE
authors.lastname: Kochevar
mesh_terms: D000042:Absorption / Q000187:drug effects / Q000528:radiation effects; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001585:Benzoyl Peroxide / Q000493:pharmacokinetics / Q000494:pharmacology*; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D002462:Cell Membrane / Q000528:radiation effects* / Q000648:ultrastructure; D002463:Cell Membrane Permeability / Q000187:drug effects; D007834:Lasers; D007939:Leukemia L1210 / Q000473:pathology*; D008563:Membrane Lipids / Q000378:metabolism*; D051379:Mice; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D008563:Membrane Lipids; D017392:Thiobarbituric Acid Reactive Substances; D002084:Butylated Hydroxytoluene; D001585:Benzoyl Peroxide