title: Combined molecular MRI and immuno-spin-trapping for in vivo detection of free radicals in orthotopic mouse GL261 gliomas.
abstract: Free radicals play a major role in gliomas. By combining immuno-spin-trapping (IST) and molecular magnetic resonance imaging (mMRI), in vivo levels of free radicals were detected within mice bearing orthotopic GL261 gliomas. The nitrone spin trap DMPO (5,5-dimethyl pyrroline N-oxide) was administered prior to injection of an anti-DMPO probe (anti-DMPO antibody covalently bound to a bovine serum albumin (BSA)-Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-biotin MRI contrast agent) to trap tumor-associated free radicals. mMRI detected the presence of anti-DMPO adducts by either a significant sustained increase (p<0.001) in MR signal intensity or a significant decrease (p<0.001) in T1 relaxation, measured as %T1 change. In vitro assessment of the anti-DMPO probe indicated a significant decrease (p<0.0001) in T1 relaxation in GL261 cells that were oxidatively stressed with hydrogen peroxide, compared to controls. The biotin moiety of the anti-DMPO probe was targeted with fluorescently-labeled streptavidin to locate the anti-DMPO probe in excised brain tissues. As a negative control a non-specific IgG antibody covalently bound to the albumin-Gd-DTPA-biotin construct was used. DMPO adducts were also confirmed in tumor tissue from animals administered DMPO, compared to non-tumor brain tissue. GL261 gliomas were found to have significantly increased malondialdehyde (MDA) protein adducts (p<0.001) and 3-nitrotyrosine (3-NT) (p<0.05) compared to normal mouse brain tissue, indicating increased oxidized lipids and proteins, respectively. Co-localization of the anti-DMPO probe with either 3-NT or 4-hydroxynonenal was also observed. This is the first report regarding the detection of in vivo levels of free radicals from a glioma model.
authors: Advanced Magnetic Resonance Center, Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. Electronic address: Rheal-Towner@omrf.org.
authors: Rheal A
authors: RA
authors: Towner
authors: Nataliya
authors: N
authors: Smith
authors: Debra
authors: D
authors: Saunders
authors: Patricia Coutinho
authors: PC
authors: De Souza
authors: Leah
authors: L
authors: Henry
authors: Florea
authors: F
authors: Lupu
authors: Robert
authors: R
authors: Silasi-Mansat
authors: Marilyn
authors: M
authors: Ehrenshaft
authors: Ronald P
authors: RP
authors: Mason
authors: Sandra E
authors: SE
authors: Gomez-Mejiba
authors: Dario C
authors: DC
authors: Ramirez
mesh_terms: D000418:Albumins; D000818:Animals; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D003287:Contrast Media; D003497:Cyclic N-Oxides / Q000276:immunology*; D004195:Disease Models, Animal; D005609:Free Radicals / Q000032:analysis* / Q000302:isolation & purification; D019786:Gadolinium DTPA; D005910:Glioma / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D007074:Immunoglobulin G / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D051379:Mice; D008810:Mice, Inbred C57BL; D009589:Nitrogen Oxides / Q000378:metabolism; D010084:Oxidation-Reduction; D011859:Radiography; D013113:Spin Labels / Q000138:chemical synthesis; D019097:Spin Trapping; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000418:Albumins; D003287:Contrast Media; D003497:Cyclic N-Oxides; D005609:Free Radicals; D007074:Immunoglobulin G; D009589:Nitrogen Oxides; D013113:Spin Labels; C058946:albumin-(gadolinium-DTPA); C015388:nitrones; C002744:3-nitrotyrosine; D014443:Tyrosine; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D019786:Gadolinium DTPA
keywords: 3-NT; 3-nitrotyrosine; 4-hydroxynonenal; 5,5 dimethyl-1-pyrroline-N-oxide; Anti-DMPO probe; BSA; DMPO; EDC; Free radical; Gd-DTPA; Glioma; HN; IHC; IST; IgG; IgG contrast agent; IgG-albumin–Gd-DTPA–biotin; Immuno-spin-trapping; In vivo; MDA; MRI; Molecular magnetic resonance imaging; Mouse; N-succinimidyl 3-(2-pyridyldithio)-propionate; N-succinimidyl-S-acetylthioacetate; NHS; PBS; ROIs; ROS/RNS; TE; TR; anti-DMPO antibody–albumin–Gd-DTPA–biotin; bovine serum albumin; echo time; gadolinium-diethylene triamine penta acetic acid; immuno-spin-trapping; immunoglobulin G; immunohistochemistry; mMRI; magnetic resonance imaging; malondialedhyde; molecular MRI; phosphate buffer saline; reactive oxygen (nitrogen) species; regions of interest; repetition time