title: Redox evaluation in sepsis model mice by the in vivo ESR technique using acyl-protected hydroxylamine.
abstract: In vivo electron spin resonance (ESR) spectroscopy is a noninvasive technique that measures the oxidative stress in living experimental animals. The rate of decay of the ESR signal right after an injection of nitroxyl radical has been measured to evaluate the oxidative stress in animals, although the probe's disposition could also affect this rate. Because the amount of probes forming the redox pair of hydroxyl amine and its corresponding nitroxyl radical was shown to be nearly constant in most organs or tissues 10min after the injection of 1-acetoxy-3-carbamoyl-2,2,5,5-tetramethylpyrrolidine (ACP) in mice, we evaluated the oxidative stress in sepsis model mice induced by lipopolysaccharide (LPS) by intravenously injecting ACP as a precursor of redox probes. The in vivo ESR signal increased up to 7-8min after the ACP injection and then decreased. Decay of the in vivo signal in LPS-treated mice was significantly slower than that in healthy mice, whereas no significant difference was observed in the rate of change in the total amount of redox probes in the blood and liver between these groups. ESR imaging showed that the in vivo signals observed at the chest and upper abdomen decayed slowly in LPS-treated mice. Suppression of the decay in LPS-treated mice was canceled by the administration of a combination of pegylated superoxide dismutase and catalase, or an inhibitor of nitric oxide synthase, or gadolinium chloride. These results indicate that the LPS-treated mouse is under oxidative stress and that reactive oxygen species, such as superoxide and peroxynitrite, related to macrophages are mainly involved in the oxidative stress.
authors.affiliation: Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Okazaki
authors.affiliation: Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Tachibana
authors.affiliation: Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Koga-Ogawa
authors.affiliation: Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan; National Institute of Radiological Sciences, Chiba 263-8555, Japan. Electronic address: keizo@ph.sojo-u.ac.jp.
authors.forename: Keizo
authors.initials: K
authors.lastname: Takeshita
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004578:Electron Spin Resonance Spectroscopy; D019811:Hydroxylamine / Q000008:administration & dosage*; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D051379:Mice; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D011759:Pyrrolidines / Q000008:administration & dosage; D017382:Reactive Oxygen Species / Q000378:metabolism; D018805:Sepsis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology
chemical_list: C416858:1-acetoxy-3-carbamoyl-2,2,5,5-tetramethylpyrrolidine; D008070:Lipopolysaccharides; D011759:Pyrrolidines; D017382:Reactive Oxygen Species; D019811:Hydroxylamine
keywords: Acyl-protected hydroxylamine; Free radicals; In vivo ESR; Nitroxyl radical; Oxidative stress; Reactive oxygen species; Redox; Sepsis