title: Oxygen concentration dependence of lipid peroxidation and lipid-derived radical generation: application of profluorescent nitroxide switch.
abstract: Lipid-derived radicals and peroxides are involved in the pathogenesis of oxidative stress diseases and, although lipid peroxide production is a required reaction between a lipid radical and molecular oxygen, a useful lipid radical detection method has remained tentative. Also, the effect of oxygen concentration on lipid peroxide production must be considered because of the hypoxic conditions in cancer and ischemic regions. In this study, the focus was on nitroxide reactivity, which allows spin trapping with carbon-centred radicals via radical-radical reactions and fluorophore quenching through interactions with nitroxide's unpaired electron. Thus, the aim here was to demonstrate a useful detection method for lipid-derived radicals as well as to clarify the effects of oxygen concentration on lipid peroxide production using profluorescent nitroxide. This latter compound reacted with lipid-derived radicals in a manner inversely dependent on oxygen concentration, resulting in fluorescence due to alkoxyamine formation and, conversely, lipid peroxide concentrations decreased with lower oxygen in the reaction system. Furthermore, nitroxide inhibited lipid peroxide production and stopped oxygen consumption in the same solution. These results suggested that the novel application of profluorescent nitroxide could directly and sensitively detect lipid-derived radicals and that radical and peroxide production were dependent on oxygen concentration.
authors: Department of Bio-functional Science, Faculty of Pharmaceutical Sciences, Kyushu University, Maidashi, Fukuoka, Japan.
authors: Fumiya
authors: F
authors: Mito
authors: Kana
authors: K
authors: Kitagawa
authors: Toshihide
authors: T
authors: Yamasaki
authors: Chisato
authors: C
authors: Shirahama
authors: Taketoshi
authors: T
authors: Oishi
authors: Yuko
authors: Y
authors: Ito
authors: Mayumi
authors: M
authors: Yamato
authors: Ken-Ichi
authors: K
authors: Yamada
mesh_terms: D000818:Animals; D004578:Electron Spin Resonance Spectroscopy; D005453:Fluorescence; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism*; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism; D015227:Lipid Peroxidation / Q000502:physiology*; D008054:Lipid Peroxides / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism*; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D005609:Free Radicals; D008054:Lipid Peroxides; D017392:Thiobarbituric Acid Reactive Substances; D009569:Nitric Oxide; D019787:Linoleic Acid; D010100:Oxygen