title: Oxygen therapy improves energy metabolism in focal cerebral ischemia.
abstract: Oxygen therapy (OT) with hyperbaric oxygen (HBO) or normobaric hyperoxia (NBO) improves the oxygenation of penumbral tissue in experimental ischemic stroke. However, whether this results in the improvement of energy metabolism is unclear. We investigated the effect of both OTs on tissue acidosis and on ATP production. Beginning 25 min after filament middle cerebral artery occlusion (MCAO), mice breathed either air, 100% O₂ (NBO), or 100% O₂ at 3 ata (HBO) for 60 min. Regional tissue pH was measured using the umbelliferone fluorescence. Regional ATP concentration was depicted by substrate-specific bioluminescence. Severity of ischemia did not differ among groups in laser-Doppler flowmetry. Both NBO (70.1±14.0 mm³) and, more effectively, HBO (57.2±11.9 mm³) significantly reduced volume of tissue acidosis compared to air (89.4±4.0 mm³), p<0.05). Topographically, acidosis was less pronounced in the medial striatum and in the cortical ischemic border areas. This resulted in significantly smaller volumes of ATP depletion (77.8±7.7 mm³ in air, 61.4±15.2 mm³ in NBO and 51.2±14.4 mm³ in HBO; p<0.05). In conclusion, OT significantly improves energy metabolism in the border zones of focal cerebral ischemia which are the areas protected by OT in this model.
authors.affiliation: Departments of Neurology, Ruprecht-Karls-University Heidelberg, Germany.
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.forename: Hartmut
authors.initials: H
authors.lastname: Strelow
authors.forename: Günter
authors.initials: G
authors.lastname: Mies
authors.forename: Roland
authors.initials: R
authors.lastname: Veltkamp
mesh_terms: D000138:Acidosis / Q000209:etiology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism* / Q000628:therapy*; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010100:Oxygen / Q000378:metabolism*; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D014468:Umbelliferones
chemical_list: D008565:Membrane Proteins; D014468:Umbelliferones; C519752:penumbra protein, mouse; C031477:7-hydroxycoumarin; D000255:Adenosine Triphosphate; D010100:Oxygen