title: In vivo detection of free radicals in mouse septic encephalopathy using molecular MRI and immuno-spin trapping.
abstract: Free radicals are known to play a major role in sepsis. Combined immuno-spin trapping and molecular magnetic resonance imaging (MRI) was used to detect in vivo and in situ levels of free radicals in murine septic encephalopathy after cecal ligation and puncture (CLP). DMPO (5,5-dimethyl pyrroline N-oxide) was injected over 6h after CLP, before administration of an anti-DMPO probe (anti-DMPO antibody bound to albumin-gadolinium-diethylene triamine pentaacetic acid-biotin MRI targeting contrast agent). In vitro assessment of the anti-DMPO probe in oxidatively stressed mouse astrocytes significantly decreased T1 relaxation (p < 0.0001) compared to controls. MRI detected the presence of anti-DMPO adducts via a substantial decrease in %T1 change within the hippocampus, striatum, occipital, and medial cortex brain regions (p < 0.01 for all) in septic animals compared to shams, which was sustained for over 60 min (p < 0.05 for all). Fluorescently labeled streptavidin was used to target the anti-DMPO probe biotin, which was elevated in septic brain, liver, and lungs compared to sham. Ex vivo DMPO adducts (qualitative) and oxidative products, including 4-hydroxynonenal and 3-nitrotyrosine (quantitative, p < 0.05 for both), were elevated in septic brains compared to shams. This is the first study that has reported on the detection of in vivo and in situ levels of free radicals in murine septic encephalopathy.
authors: Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA. Electronic address: Rheal-Towner@omrf.org.
authors: Rheal A
authors: RA
authors: Towner
authors: Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
authors: Philippe
authors: P
authors: Garteiser
authors: Instituto de Pesquisa Clinica Evandro Chagas, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brazil.
authors: Fernando
authors: F
authors: Bozza
authors: Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
authors: Nataliya
authors: N
authors: Smith
authors: Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
authors: Debra
authors: D
authors: Saunders
authors: Instituto de Pesquisa Clinica Evandro Chagas, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brazil.
authors: Joana C P
authors: JCP
authors: d'Avila
authors: Instituto de Pesquisa Clinica Evandro Chagas, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brazil.
authors: Flora
authors: F
authors: Magno
authors: Laboratório de Bioquímica de Resposta ao Estresse, Programa de Biologia Molecular e Biotecnologia, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, Brazil.
authors: Marcus F
authors: MF
authors: Oliveira
authors: Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
authors: Marilyn
authors: M
authors: Ehrenshaft
authors: Cardiovascular Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
authors: Florea
authors: F
authors: Lupu
authors: Cardiovascular Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
authors: Robert
authors: R
authors: Silasi-Mansat
authors: Laboratory of Experimental Medicine & Therapeutics, Instituto Multidisciplinario de Investigaciones Biologicas-San Luis, CONICET, National University of San Luis, San Luis 5700, Argentina.
authors: Dario C
authors: DC
authors: Ramirez
authors: Laboratory of Experimental Medicine & Therapeutics, Instituto Multidisciplinario de Investigaciones Biologicas-San Luis, CONICET, National University of San Luis, San Luis 5700, Argentina.
authors: Sandra E
authors: SE
authors: Gomez-Mejiba
authors: Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
authors: Ronald P
authors: RP
authors: Mason
authors: Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brazil.
authors: Hugo C
authors: HC
authors: Castro Faria-Neto
mesh_terms: D000447:Aldehydes / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D003497:Cyclic N-Oxides; D005609:Free Radicals / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D008810:Mice, Inbred C57BL; D018384:Oxidative Stress; D065166:Sepsis-Associated Encephalopathy / Q000378:metabolism*; D013113:Spin Labels; D019097:Spin Trapping; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000447:Aldehydes; D003497:Cyclic N-Oxides; D005609:Free Radicals; D013113:Spin Labels; C002744:3-nitrotyrosine; D014443:Tyrosine; C017245:5,5-dimethyl-1-pyrroline-1-oxide; C027576:4-hydroxy-2-nonenal
keywords: 3-NT; 3-Nitrotyrosine; 3-nitrotyrosine; 4-Hydroxynonenal; 4-hydroxynonenal; 5,5-dimethyl-1-pyrroline-N-oxide; BBB; BSA; CLP; Cecal ligation and puncture; DMPO; Fluorescence microscopy; Free radicals; Gd-DTPA; HNE; IST; Immuno-spin trapping; Mice; Molecular MRI; OMRI; Overhauser-enhanced MRI; ROS/RNS; Sepsis; anti-DMPO probe; anti-DMPO-biotin-BSA-Gd-DTPA; blood–brain-barrier; bovine serum albumin; cecal ligation and puncture; gadolinium diethylene triamine pentaacetic acid; immuno-spin trapping; in vivo; mMRI; molecular magnetic resonance imaging; reactive oxygen/nitrogen species