title: Generation of hydrogen peroxide during brief oxygen-glucose deprivation induces preconditioning neuronal protection in primary cultured neurons.
abstract: Although reactive oxygen species (ROS) have been implicated in ischemic preconditioning (IPC)-induced neuronal protection, several key questions concerning ROS remain to be elucidated. The purpose of this study is to obtain direct evidence for the formation of specific ROS species generated by IPC, and to determine the specific species that is responsible for the observed neuronal protection. Primary cultured cortex neurons from rat embryos were preconditioned with 10 min of oxygen-glucose deprivation (OGD), which increased the intracellular levels of superoxide and hydrogen peroxide. This preconditioning markedly induced neuronal protection against 2-hr OGD stimuli. Preconditioning with exogenous ROS by the administration of xanthine/xanthine oxidase (X/XO), or hydrogen peroxide was also found to induce IPC-like neuronal protection. Administration of hydrogen peroxide scavengers, such as catalase, glutathione, or the thiol reductant N-(2-mercaptopriopionyl)-glycine, all reduced the increase in the intracellular hydrogen peroxide levels, which effectively eliminated IPC- or exogenous ROS-induced neuronal protection. In contrast, administration of the membrane-permeable superoxide dismutase mimic Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride was able to block the increase of intracellular superoxide levels during IPC, but did not abolish either IPC- or exogenous X/XO preconditioning-induced neuronal protection. These findings strongly suggest that IPC enhances the generation of superoxide, which is then converted to hydrogen peroxide, and that hydrogen peroxide is likely the main trigger involved in the mechanism of IPC-induced neuronal protection.
authors.affiliation: College of Pharmacy, University of New Mexico Health Science Center, Albuquerque, NM 87131, USA.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Furuichi
authors.forename: Wenlan
authors.initials: W
authors.lastname: Liu
authors.forename: Honglian
authors.initials: H
authors.lastname: Shi
authors.forename: Minoru
authors.initials: M
authors.lastname: Miyake
authors.forename: Ke Jian
authors.initials: KJ
authors.lastname: Liu
mesh_terms: D000818:Animals; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004622:Embryo, Mammalian; D005260:Female; D019793:Fluorescein; D016166:Free Radical Scavengers / Q000494:pharmacology; D005947:Glucose / Q000172:deficiency*; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D000860:Hypoxia; D007211:Indoles; D019194:Ischemic Preconditioning / Q000379:methods*; D008665:Metalloporphyrins / Q000494:pharmacology; D009474:Neurons / Q000502:physiology*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors
chemical_list: D016166:Free Radical Scavengers; D007211:Indoles; D008665:Metalloporphyrins; D017382:Reactive Oxygen Species; D013481:Superoxides; C007293:DAPI; C050950:tetrakis(N-methyl-4-pyridiniumyl)porphine manganese(III) complex; D006861:Hydrogen Peroxide; D005947:Glucose; D019793:Fluorescein