Abramov, A.Y.;
Scorziello, A.;
Duchen, M.R.;
(2007)
Three distinct mechanisms generate oxygen free radicals in neurons and contribute to cell death during anoxia and reoxygenation.
Journal of Neuroscience
, 27
(5)
pp. 1129-1138.
10.1523/JNEUROSCI.4468-06.2007.
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Abstract
Ischemia is a major cause of brain damage, and patient management is complicated by the paradoxical injury that results from reoxygenation. We have now explored the generation of reactive oxygen species (ROS) in hippocampal and cortical neurons in culture in response to oxygen and glucose deprivation or metabolic inhibition and reoxygenation. Fluorescence microscopy was used to measure the rate of ROS generation using hydroethidine, dicarboxyfluorescein diacetate, or MitoSOX. ROS generation was correlated with changing mitochondrial potential (rhodamine 123), [Ca2+]c (fluo-4, fura-2, or Indo-1), or ATP consumption, indicated by increased [Mg2+]c. We found that three distinct mechanisms contribute to neuronal injury by generating ROS and oxidative stress, each operating at a different stage of ischemia and reperfusion. In response to hypoxia, mitochondria generate an initial burst of ROS, which is curtailed once mitochondria depolarize or prevented by previous depolarization with uncoupler. A second phase of ROS generation that followed after a delay was blocked by the xanthine oxidase (XO) inhibitor oxypurinol. This phase correlated with a rise in [Mg2+]c, suggesting XO activation by accumulating products of ATP consumption. A third phase of ROS generation appeared at reoxygenation. This was blocked by NADPH oxidase inhibitors and was absent in cells from gp91phox–/– knock-out mice. It was Ca2+ dependent, suggesting activation by increased [Ca2+]c during anoxia, itself partly attributable to glutamate release. Inhibition of either the NADPH oxidase or XO was significantly neuroprotective. Thus, oxidative stress contributes to cell death over and above the injury attributable to energy deprivation.
| Type: | Article |
|---|---|
| Title: | Three distinct mechanisms generate oxygen free radicals in neurons and contribute to cell death during anoxia and reoxygenation |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1523/JNEUROSCI.4468-06.2007 |
| Publisher version: | http://dx.doi.org/10.1523/JNEUROSCI.4468-06.2007 |
| Language: | English |
| Additional information: | Published by the Society of Neuroscience This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. The license allows you to copy, distribute, and transmit the work, as well as adapting it. However, you must attribute the work to the author (but not in any way that suggests that they endorse you or your use of the work), and cannot use the work for commercial purposes without prior permission of the author. If you alter or build upon this work, you can distribute the resulting work only under the same or similar license to this one. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA. |
| Keywords: | Ischemia, neurons, reactive oxygen species, mitochondria, xanthine oxidase, NADPH oxidase |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10406 |
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