On the use of fluorescence lifetime imaging and dihydroethidium to detect superoxide in intact animals and ex vivo tissues: a reassessment. Free Radic Biol Med 2014 Feb;67:278-84
Date
11/10/2013Pubmed ID
24200598Pubmed Central ID
PMC4275029DOI
10.1016/j.freeradbiomed.2013.10.816Scopus ID
2-s2.0-84889578332 (requires institutional sign-in at Scopus site) 53 CitationsAbstract
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(-)) 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(-) 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(-) 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(-). 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(-) reaction with HE.
Author List
Michalski R, Michalowski B, Sikora A, Zielonka J, Kalyanaraman BAuthors
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of WisconsinJacek M. Zielonka PhD Assistant Professor in the Biophysics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsBrain
Brain Mapping
Ethidium
Fluorescent Dyes
NADPH Oxidases
Superoxides