title: Increased mitochondrial DNA oxidative damage after transient middle cerebral artery occlusion in mice.
abstract: Oxidative stress and DNA oxidation play important roles in the induction of ischemic neuronal cell death. However, the subcellular source of oxidized DNA detected by 8-hydroxy-2'-deoxyguanosine (8-OHdG) after ischemia has not been clarified although it is known to increase in the brain after ischemia. One-hour transient ischemia of the middle cerebral artery was induced in mice utilizing an intraluminal filament. The occurrence of superoxide anion as an ethidium (Et) signal, 8-OHdG, cytochrome c release and neuronal cell death were examined using immunohistological and biochemical techniques in sham-operated control (0h) and 1, 3, 6, 24, or 96h after reperfusion. Et signals were prominent in the cortical neurons of ipsilateral hemisphere 3h after reperfusion. Strong 8-OHdG immunoreactivity was observed 3-6h after reperfusion. Immunoassays after cell fractionation revealed a significant increase of 8-OHdG in mitochondria 6h after reperfusion. Immunohistochemistry revealed that the 8-OHdG immunoreactivity colocalized with a neuronal marker, microfilament 200 and a mitochondrial marker, cytochrome oxidase subunit I. Cytochrome c rose in cytoplasm at 6h and TUNEL-positive neurons noted 6-24h after ischemia. The present results suggest the possibility that the mitochondrial damage including mitochondrial DNA oxidation might be responsible for the induction of ischemic neuronal cell death.
authors.affiliation: Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Ohtaki
authors.forename: Takaaki
authors.initials: T
authors.lastname: Takeda
authors.forename: Kenji
authors.initials: K
authors.lastname: Dohi
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yofu
authors.forename: Tomoya
authors.initials: T
authors.lastname: Nakamachi
authors.forename: Kazue
authors.initials: K
authors.lastname: Satoh
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hiraizumi
authors.forename: Hideyo
authors.initials: H
authors.lastname: Miyaoka
authors.forename: Masaji
authors.initials: M
authors.lastname: Matsunaga
authors.forename: Seiji
authors.initials: S
authors.lastname: Shioda
mesh_terms: D000818:Animals; D045304:Cytochromes c / Q000378:metabolism; D004249:DNA Damage; D004272:DNA, Mitochondrial / Q000378:metabolism*; D003839:Deoxyadenosines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D007839:Functional Laterality; D020287:In Situ Nick-End Labeling / Q000379:methods; D007211:Indoles; D020244:Infarction, Middle Cerebral Artery / Q000503:physiopathology*; D051379:Mice; D016900:Neurofilament Proteins / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015424:Reperfusion; D013997:Time Factors
chemical_list: C436623:8-hydroxy-2'-deoxyadenosine; D004272:DNA, Mitochondrial; D003839:Deoxyadenosines; D007211:Indoles; D016900:Neurofilament Proteins; D017382:Reactive Oxygen Species; C051774:neurofilament protein H; C007293:DAPI; D045304:Cytochromes c; D010751:Phosphopyruvate Hydratase