title: Assessment at the single-cell level identifies neuronal glutathione depletion as both a cause and effect of ischemia-reperfusion oxidative stress.
abstract: Oxidative stress contributes to neuronal death in brain ischemia-reperfusion. Tissue levels of the endogenous antioxidant glutathione (GSH) are depleted during ischemia-reperfusion, but it is unknown whether this depletion is a cause or an effect of oxidative stress, and whether it occurs in neurons or other cell types. We used immunohistochemical methods to evaluate glutathione, superoxide, and oxidative stress in mouse hippocampal neurons after transient forebrain ischemia. GSH levels in CA1 pyramidal neurons were normally high relative to surrounding neuropil, and exhibited a time-dependent decrease during the first few hours of reperfusion. Colabeling for superoxide in the neurons showed a concurrent increase in detectable superoxide over this interval. To identify cause-effect relationships between these changes, we independently manipulated superoxide production and GSH metabolism during reperfusion. Mice in which NADPH oxidase activity was blocked to prevent superoxide production showed preservation of neuronal GSH content, thus demonstrating that neuronal GSH depletion is result of oxidative stress. Conversely, mice in which neuronal GSH levels were maintained by N-acetyl cysteine treatment during reperfusion showed less neuronal superoxide signal, oxidative stress, and neuronal death. At 3 d following ischemia, GSH content in reactive astrocytes and microglia was increased in the hippocampal CA1 relative to surviving neurons. Results of these studies demonstrate that neuronal GSH depletion is both a result and a cause of neuronal oxidative stress after ischemia-reperfusion, and that postischemic restoration of neuronal GSH levels can be neuroprotective.
authors.affiliation: Departments of Neurology, University of California San Francisco, and Neurology Service, San Francisco Veterans Affairs Medical Center (SFVAMC), San Francisco, California 94121 Seokjoon.won@va.gov.
authors.forename: Seok Joon
authors.initials: SJ
authors.lastname: Won
authors.affiliation: Departments of Neurology, University of California San Francisco, and Neurology Service, San Francisco Veterans Affairs Medical Center (SFVAMC), San Francisco, California 94121.
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Kim
authors.affiliation: Departments of Neurology, University of California San Francisco, and Neurology Service, San Francisco Veterans Affairs Medical Center (SFVAMC), San Francisco, California 94121.
authors.forename: Giordano Fabricio
authors.identifier: http://orcid.org/0000-0003-2930-1854
authors.initials: GF
authors.lastname: Cittolin-Santos
authors.affiliation: Departments of Neurology, University of California San Francisco, and.
authors.forename: Raymond A
authors.identifier: http://orcid.org/0000-0002-3664-5359
authors.initials: RA
authors.lastname: Swanson
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D005978:Glutathione / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D018384:Oxidative Stress / Q000502:physiology*; D015427:Reperfusion Injury / Q000209:etiology / Q000378:metabolism* / Q000473:pathology
chemical_list: D005978:Glutathione
keywords: N-acetyl cysteine; glutathione; hyperglycemia; ischemia; neuron; oxidative stress