title: In vivo real-time measurement of superoxide anion radical with a novel electrochemical sensor.
abstract: The dynamics of superoxide anion (O(2)(-)) in vivo remain to be clarified because no appropriate method exists to directly and continuously monitor and evaluate O(2)(-) in vivo. Here, we establish an in vivo method using a novel electrochemical O(2)(-) sensor. O(2)(-) generated is measured as a current and evaluated as a quantified partial value of electricity (Q(part)), which is calculated by integration of the difference between the baseline and the actual reacted current. The accuracy and efficacy of this method were confirmed by dose-dependent O(2)(-) generation in xanthine-xanthine oxidase in vitro in phosphate-buffered saline and human blood. It was then applied to endotoxemic rats in vivo. O(2)(-) current began to increase 1 h after lipopolysaccharide, and Q(part) increased significantly for 6 h in endotoxemic rats, in comparison to sham-treated rats. These values were attenuated by superoxide dismutase. The generation and attenuation of O(2)(-) were indirectly confirmed by plasma lipid peroxidation with malondialdehyde, endothelial injury with soluble intercellular adhesion molecule-1, and microcirculatory dysfunction. This is a novel method for measuring O(2)(-) in vivo and could be used to monitor and treat the pathophysiology caused by excessive O(2)(-) generation in animals and humans.
authors.affiliation: Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, Ube 755-8505, Japan. motoki-ygc@umin.ac.jp
authors.forename: Motoki
authors.initials: M
authors.lastname: Fujita
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Tsuruta
authors.forename: Shunji
authors.initials: S
authors.lastname: Kasaoka
authors.forename: Kenji
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Ryo
authors.initials: R
authors.lastname: Tanaka
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Oda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nanba
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Igarashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Yuasa
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Maekawa
mesh_terms: D000818:Animals; D000838:Anions / Q000032:analysis; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D004566:Electrodes; D005609:Free Radicals / Q000032:analysis*; D006801:Humans; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D015203:Reproducibility of Results; D013481:Superoxides / Q000032:analysis*; D013997:Time Factors
chemical_list: D000838:Anions; D005609:Free Radicals; D013481:Superoxides