On the use of fluorescence lifetime imaging and dihydroethidium to detect superoxide in intact animals and ex vivo tissues: A reassessment

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• 作者：Radoslaw Michalski ; Bartosz Michalowski ; Adam Sikora ; Jacek Zielonka ; Balaraman Kalyanaraman
• 关键词：2-OH-E+ ; 2-hydroxyethidium ; DE ; deuteroethidine ; DHE ; dihydroethidium ; dtpa ; diethylenetriaminepentaacetate ; E+ ; ethidium ; HE ; hydroethidine ; HX ; hypoxanthine ; X ; xanthine ; XO ; xanthine oxidase ; HRP ; horseradish peroxidase ; TFA ; trifluoroacetic acid
• 刊名：Free Radical Biology and Medicine
• 出版年：February, 2014
• 年：2014
• 卷：67
• 期：Complete
• 页码：278-284
• 全文大小：1746 K

文摘

Recently, D.J. Hall et al. reported that ethidium (E⁺) is formed as a major product of hydroethidine (HE) or dihydroethidium reaction with superoxide (O₂^{鈭?/sup>) in intact animals with low tissue oxygen levels (J. Cereb. Blood Flow Metab. 32:23-32, 2012). The authors concluded that measurement of E+ is an indicator of O₂鈭?/sup> formation in intact brains of animals. This finding is in stark contrast to previous reports using in vitro systems showing that 2-hydroxyethidium, not ethidium, is formed from the reaction between O₂鈭?/sup> and HE. Published in vivo results support the in vitro findings. In this study, we performed additional experiments in which HE oxidation products were monitored under different fluxes of O₂鈭?/sup>. Results from these experiments further reaffirm our earlier findings (H. Zhao et al., Free Radic. Biol. Med. 34:1359, 2003). We conclude that whether in vitro or in vivo, E+ measured by HPLC or by fluorescence lifetime imaging is not a diagnostic marker product for O₂鈭?/sup> reaction with HE.}