In vivo real-time measurement of superoxide anion radical with a novel electrochemical sensor.
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.
Fujita
Motoki
M
Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, Ube 755-8505, Japan. motoki-ygc@umin.ac.jp
Tsuruta
Ryosuke
R
Kasaoka
Shunji
S
Fujimoto
Kenji
K
Tanaka
Ryo
R
Oda
Yasutaka
Y
Nanba
Masahiro
M
Igarashi
Masatsugu
M
Yuasa
Makoto
M
Yoshikawa
Toshikazu
T
Maekawa
Tsuyoshi
T
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
D000838:Anions; D005609:Free Radicals; D013481:Superoxides