title: Hyperbaric oxygen and hyperbaric air preconditioning induces ischemic tolerance to transient forebrain ischemia in the gerbil.
abstract: Ischemic preconditioning with sublethal stress triggers defensive mechanisms against ischemic brain damage; however, such manipulations are potentially dangerous and, therefore, safe stimuli have been sought. Hyperoxia preconditioning by administration of hyperbaric (HBO) or normobaric oxygen (NBO) may have neuroprotective potential. The aim of this study was to determine whether preconditioning with HBO and air (HBA) applied at 2.5 absolute pressure (ATA) or NBO preconditioning induces ischemic tolerance in the brain of gerbils subjected to 3min transient cerebral ischemia. Neuronal cell survival, changes in brain temperature, the generation of factors involved in neurodegeneration and basic behavior in nest building were all tested. Hyperoxic preconditioning prevented ischemia-induced neuronal cell loss, reduced the number of TUNEL positive cells in the CA1 region of the hippocampus and improved the nest building process compared to untreated ischemic animals. Preconditioning also suppressed the production of reactive oxygen species and increased Bax expression normally observed after an ischemic episode. Only HBO preconditioning inhibited ischemia-evoked increases in brain temperature. Our results show that hyperoxic preconditioning results in induction of ischemic tolerance and prevents ischemia-induced neuronal damage in the gerbil brain. Pressurized air preconditioning was as effective as HBO or NBO preconditioning in providing neuroprotection. The observed neuroprotection probably results from mild oxidative stress evoked by increased brain tissue oxidation and activation of antioxidant and antiapoptotic defenses.
authors.affiliation: Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Gamdzyk
authors.affiliation: Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Małek
authors.affiliation: Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Bratek
authors.affiliation: Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Koks
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Lublin, Lublin, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kaminski
authors.affiliation: Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Apolonia
authors.initials: A
authors.lastname: Ziembowicz
authors.affiliation: Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland. Electronic address: esalinska@imdik.pan.pl.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Salinska
mesh_terms: D000818:Animals; D017209:Apoptosis; D001831:Body Temperature; D001921:Brain / Q000378:metabolism; D002470:Cell Survival; D005849:Gerbillinae; D006624:Hippocampus / Q000473:pathology; D006931:Hyperbaric Oxygenation / Q000379:methods*; D002546:Ischemic Attack, Transient / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D019194:Ischemic Preconditioning / Q000379:methods*; D008297:Male; D009425:Nesting Behavior; D016548:Prosencephalon / Q000503:physiopathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein
keywords: Brain ischemia; Hyperbaric oxygen; Hyperoxic preconditioning; Neuroprotection