tailieunhanh - Region-specific effects on brain metabolites of hypoxia and hyperoxia overlaid on cerebral ischemia in young and old rats: a quantitative proton magnetic resonance spectroscopy stud

Both hypoxia and hyperoxia, deregulating the oxidative balance, may play a role in the pathology of neurodegenerative disorders underlain by cerebral ischemia. In the present study, quantitative proton magnetic resonance spectroscopy was used to evaluate regional metabolic alterations, following a 24-hour hypoxic or hyperoxic exposure on the background of ischemic brain insult, in two | Macri et al. Journal of Biomedical Science 2010 17 14 http content 17 1 14 I NSC The cost of publication in Journal of Biomedical Science is bourne by the National Science Council Taiwan. JOURNAL OF BIOMEDICAL SCIENCE RESEARCH Open Access Region-specific effects on brain metabolites of hypoxia and hyperoxia overlaid on cerebral ischemia in young and old rats a quantitative proton magnetic resonance spectroscopy study Maria A Macri1 Nicola DAlessandro2 Camillo Di Giulio3 Patrizia Di Iorio4 Silvano Di Luzio5 Patricia Giuliani4 Ennio Esposito6 and Mieczyslaw Pokorski 7 Abstract Background Both hypoxia and hyperoxia deregulating the oxidative balance may play a role in the pathology of neurodegenerative disorders underlain by cerebral ischemia. In the present study quantitative proton magnetic resonance spectroscopy was used to evaluate regional metabolic alterations following a 24-hour hypoxic or hyperoxic exposure on the background of ischemic brain insult in two contrasting age-groups of rats young - 3 months old and aged - 24 months old. Methods Cerebral ischemia was induced by ligation of the right common carotid artery. Concentrations of eight metabolites alanine choline-containing compounds total creatine Y-aminobutyric acid glutamate lactate myoinositol and N-acetylaspartate were quantified from extracts in three different brain regions fronto-parietal and occipital cortices and the hippocampus from both hemispheres. Results In the control normoxic condition there were significant increases in lactate and myo-inositol concentrations in the hippocampus of the aged rats compared with the respective values in the young ones. In the ischemia-hypoxia condition the most prevalent changes in the brain metabolites were found in the hippocampal regions of both young and aged rats but the effects were more evident in the aged animals. The ischemia-hyperoxia procedure caused less dedicated changes in the brain metabolites which may reflect more limited