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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

11/10/2013

Pubmed ID

24200598

Pubmed Central ID

PMC4275029

DOI

10.1016/j.freeradbiomed.2013.10.816

Scopus ID

2-s2.0-84889578332 (requires institutional sign-in at Scopus site)   53 Citations

Abstract

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 B

Authors

Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin
Jacek 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

Animals
Brain
Brain Mapping
Ethidium
Fluorescent Dyes
NADPH Oxidases
Superoxides