The dynamics of superoxide anion (O2−) in vivo remain to be clarified because no appropriate method exists to directly and continuously monitor and evaluate O2− in vivo. Here, we establish an in vivo method using a novel electrochemical O2− sensor. O2− generated is measured as a current and evaluated as a quantified partial value of electricity (Qpart), 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 O2− generation in xanthine–xanthine oxidase in vitro in phosphate-buffered saline and human blood. It was then applied to endotoxemic rats in vivo. O2− current began to increase 1 h after lipopolysaccharide, and Qpart 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 O2− 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 O2− in vivo and could be used to monitor and treat the pathophysiology caused by excessive O2− generation in animals and humans.
"The measurement solution should be operated at a constant and high stirring speed (1,000 rpm) to acquire reproducible results. A peak-like response was observed, which is in agreement with a report by other worker (Lisdat et al. 1999, Di et al. 2004, Fujita et al. 2009, Di et al. 2007, Wang et al. 2009). A calibration plot as a function of increasing xanthine concentration for the CMC–G–SOD biosensor was obtained previously by ourself (Kocabay et al. 2012) (Figure 1). "
[Show abstract][Hide abstract] ABSTRACT: A novel highly sensitive electrochemical carboxymethylcellulose-gelatin-superoxide dismutase biosensor was used for the determination of superoxide radicals enhancement in tomato plants exposed to salinity, drought, cold and heavy metal stress. The variations in superoxide radicals depending on abiotic stress was determined using biosensor. The superoxide radical production with regard to control rapidly was increased in tomato plants exposed to salinity, drought, cold and heavy metal stress. The superoxide radical enhancement in tomato plants exposed to salinity, drought, cold and heavy metal stress was successfully determined using carboxymethylcellulose-gelatin-superoxide dismutase biosensor.
Artificial Cells Blood Substitutes and Biotechnology (formerly known as Artificial Cells Blood Substitutes and Immobilization Bi 10/2012; 41(5). DOI:10.3109/10731199.2012.717944 · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel electrochemical sensor was used in this study to determine the correlations between jugular venous O(2)(-) and HMGB1, malondialdehyde (MDA), and intercellular adhesion molecule-1 (ICAM-1) in rats with forebrain ischemia/reperfusion (FBI/R). Twenty-one male rats were divided into a Sham group, a hemorrhagic shock/reperfusion (HS/R) group, and a forebrain ischemia/reperfusion (FBI/R) group. The O(2)(-) sensor in the jugular vein detected the current derived from O(2)(-) generation (abbreviated as "O(2)(-) current"), which was integrated as the partial value of quantified electricity during ischemia (Q(I)) and after reperfusion (Q(R)). The plasma O(2)(-) current showed a gradual increase during forebrain ischemia in the HS/R and the FBI/R groups. The current showed a marked increase immediately after reperfusion and continued for more than 60 min in the FBI/R group. In the HS/R group, the current was gradually attenuated to the baseline level. Brain and plasma HMGB1 increased significantly in the FBI/R group compared with those in the Sham and the HS/R groups, and both brain and plasma HMGB1 correlated significantly with the sum of Q(I) and Q(R) (total Q). Brain and plasma MDA and plasma soluble ICAM-1 also correlated significantly with total Q. Here, we report the correlation between O(2)(-) and HMGB1, MDA, and sICAM-1 in rats with cerebral ischemia-reperfusion, using a novel electrochemical sensor. These data indicated that excessive production of O(2)(-) after ischemia-reperfusion was associated with early inflammation, oxidative stress, and endothelial activation in the brain and plasma, which might enhance the ischemia-reperfusion injury.
Brain research 08/2009; 1292:180-90. DOI:10.1016/j.brainres.2009.07.054 · 2.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We recently reported that excessive superoxide anion radical (O(2)(-)) was generated in the jugular vein during reperfusion in rats with forebrain ischemia/reperfusion using a novel electrochemical sensor and excessive O(2)(-) generation was associated with oxidative stress, early inflammation, and endothelial injury. However, the source of O(2)(-) was still unclear. Therefore, we used allopurinol, a potent inhibitor of xanthine oxidase (XO), to clarify the source of O(2)(-) generated in rats with forebrain ischemia/reperfusion. The increased O(2)(-) current and the quantified partial value of electricity (Q), which was calculated by the integration of the current, were significantly attenuated after reperfusion by pretreatment with allopurinol. Malondialdehyde (MDA) in the brain and plasma, high-mobility group box 1 (HMGB1) in plasma, and intercellular adhesion molecule-1 (ICAM-1) in the brain and plasma were significantly attenuated in rats pretreated with allopurinol with dose-dependency in comparison to those in control rats. There were significant correlations between total Q and MDA, HMGB, or ICAM-1 in the brain and plasma. Allopurinol pretreatment suppressed O(2)(-) generation in the brain-perfused blood in the jugular vein, and oxidative stress, early inflammation, and endothelial injury in the acute phase of forebrain ischemia/reperfusion. Thus, XO is one of the major sources of O(2)(-)- in blood after reperfusion in rats with forebrain ischemia/reperfusion.
Brain research 09/2009; 1305:158-67. DOI:10.1016/j.brainres.2009.09.061 · 2.84 Impact Factor
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