In vivo real-time measurement of superoxide anion radical with a novel electrochemical sensor
ABSTRACT 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.
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ABSTRACT: Superoxide anion is the key radical that causes intracellular oxidative stress. The lack of a method to directly monitor superoxide concentration in vivo in real time has severely hindered our understanding on its pathophysiology. We made transgenic zebrafish to specifically express yellow fluorescent proteins, a reversible superoxide-specific indicator, in the liver and used a fiber-optic fluorescent probe to noninvasively monitor the superoxide concentration in real time. Several superoxide-inducing and scavenging reagents were administrated onto the fish to alter superoxide concentrations. The distinct biochemical pathways of the reagents can be discerned from the transient behaviors of fluorescence time courses. These results demonstrate the feasibility of this method for analyzing superoxide dynamics and its potential as an in vivo pharmaceutical screening platform.Biomedical Optics Express 01/2013; 4(9):1702-9. DOI:10.1364/BOE.4.001702 · 3.50 Impact Factor
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ABSTRACT: A novel method for real-time monitoring of the oxidative response of a membrane-channel biomimetic system (MCBS) to free radicals is developed and the deduction of the buffering effect of MCBS is discussed.Chemical Communications 04/2013; 49(59). DOI:10.1039/c3cc41763h · 6.72 Impact Factor
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ABSTRACT: Background Bactrocera dorsalis, one of the most economically important fruit fly pests in East Asia, is well adapted to various environmental conditions. Pesticides, pathogens and other stresses can cause oxidative damage in most organisms. The superoxide dismutase (SOD) family contains some of the most important enzymes in the antioxidant protection system of the fruit fly and other organisms. ResultsFour full-length cDNA sequences encoding one MnSOD (BdSOD2-1) and three Cu-ZnSODs (BdSOD1-1, BdSOD1-2 and BdSOD1-3) were cloned. The expression profiles of these four genes under different stresses showed them to be involved in response to detrimental conditions including heavy metals, pesticides, extreme temperatures and lipopolysaccharide (LPS) stresses. More specifically, the expression levels of these genes were found to be depressed in the presence of copper, zinc and manganese. The expression of all four SOD genes increased upon exposure to lead, cadmium, low temperature (0 degrees C) and LPS stresses. Only BdSOD1-3 transcription increased significantly at high temperature (40 degrees C) exposure. The expressions levels of BdSOD1-2 and BdSOD1-3 increased significantly in the presence of -cypermethrin and malathion, but only the expression of BdSOD2-1 increased in the presence of avermectin treatment. Conclusion These different expression profiles suggest that the four BdSODs play different roles and respond to different oxidative stresses in B. dorsalis. Some BdSODs undergo specific reaction in the response to specific oxidative stresses. (c) 2013 Society of Chemical IndustryPest Management Science 12/2013; 69(12). DOI:10.1002/ps.3503 · 2.74 Impact Factor