Combined molecular MRI and immuno-spin-trapping for in vivo detection of free radicals in orthotopic mouse GL261 gliomas

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• 作者：Rheal A. Towner ; Nataliya Smith ; Debra Saunders ; Patricia Coutinho De Souza ; Leah Henry ; Florea Lupu ; Robert Silasi-Mansat ; Marilyn Ehrenshaft ; Ronald P. Mason ; S ; ra E. Gomez-Mejiba ; Dario C. Ramirez
• 关键词：Anti-DMPO probe ; anti-DMPO antibody&ndash ; albumin&ndash ; Gd-DTPA&ndash ; biotin ; BSA ; bovine serum albumin ; EDC ; N-succinimidyl 3-(2-pyridyldithio)-propionate ; Gd-DTPA ; gadolinium-diethylene triamine penta acetic acid ; HN ; 4-hydroxynonenal ; IgG ; immunoglobulin G ; IgG contrast agent ; IgG-albumin&ndash ; Gd-DTPA&ndash ; biotin ; IHC ; immunohistochemistry ; IST ; immuno-spin-trapping ; DMPO ; 5 ; 5 dimethyl-1-pyrroline-N-oxide ; MRI ; magnetic resonance imaging ; mMRI ; molecular MRI ; MDA ; malondialedhyde ; NHS ; N-su
• 刊名：Biochimica et Biophysica Acta (BBA)/Molecular Basis of Disease
• 出版年：December, 2013
• 年：2013
• 卷：1832
• 期：12
• 页码：2153-2161
• 全文大小：1634 K

文摘

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.