title: Mapping of redox status in a brain-disease mouse model by three-dimensional EPR imaging.
abstract: Electron paramagnetic resonance imaging using nitroxides is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. Typically, however, data acquisition times have been too slow to obtain a sufficient number of projections for three-dimensional images, when using continuous wave-electron paramagnetic resonance imager in small rodents, using nitroxides with comparatively short T(2) and a half-life values. Because of improvements in imagers that enable rapid data-acquisition, the feasibility of three-dimensional electron paramagnetic resonance imaging with good quality in mice was tested with nitroxides. Three-dimensional images of mice were obtained at an interval of 15 sec under field scanning of 0.3 sec and with 46 projections in the case of strong electron paramagnetic resonance signals. Three-dimensional electron paramagnetic resonance images of a blood brain barrier-permeable nitroxide, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, in the mouse head clearly showed that 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl was distributed within brain tissues, and this was confirmed by MRI observations. Based on the pharmacokinetics of nitroxides in mice, half-life mapping was demonstrated in an ischemia-reperfusion model mouse brain. Inhomogeneous half-lives were clearly mapped pixel-by-pixel in mouse head under oxidative stress by the improved continuous wave-electron paramagnetic resonance imager noninvasively.
authors.affiliation: Department of Liberal Arts and Sciences, Center for Medical Education, Sapporo Medical University, Sapporo, Hokkaido, Japan. hgfujii@sapmed.ac.jp
authors.forename: Hirotada
authors.initials: H
authors.lastname: Fujii
authors.forename: Hideo
authors.initials: H
authors.lastname: Sato-Akaba
authors.forename: Katsuya
authors.initials: K
authors.lastname: Kawanishi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirata
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D002544:Cerebral Infarction / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011759:Pyrrolidines / Q000493:pharmacokinetics*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D011759:Pyrrolidines; D017382:Reactive Oxygen Species