4-maleimido-2-2-6-6-tetramethylpiperidinooxyl and Huntington-Disease

3-nitropropionic acid (3-NP) administered systemically daily for 4 days to rats inhibits mitochondrial oxidative phosphorylation and induces selective lesions in the striatum in a manner reminiscent of Huntington's disease (HD). To investigate the potential oxidative nature of these lesions, rats were injected with 3-NP (20 mg/kg, i.p. daily for 4 days) and subsequently isolated brain synaptosomal membranes were examined for evidence of oxidative stress. Brain synaptosomal membrane proteins from rats injected with 3-NP exhibited a decreased in W/S ratio, the relevant electron paramagnetic resonance (EPR) parameter used to determine levels of protein oxidation (76% of control), and Western blot analysis for protein carbonyls revealed direct evidence of increased synaptosomal membrane protein oxidation (248% of control). Similar results were obtained in synaptosomes isolated from striatum and from cerebral cortex, demonstrating that the oxidative changes are not restricted to the lesion site. Moreover, increased oxidative stress was evident prior to the appearance of morphological lesions. These data are consistent with the hypothesis that 3-NP-induced striatal lesions, and perhaps those in HD, are associated with oxidative processes.

Topics: Animals; Blotting, Western; Cerebral Cortex; Convulsants; Corpus Striatum; Cyclic N-Oxides; Huntington Disease; Male; Nerve Tissue Proteins; Nitro Compounds; Oxidation-Reduction; Oxidative Stress; Propionates; Rats; Rats, Sprague-Dawley; Spin Labels; Synaptosomes

3-Nitropropionic acid (3-NP) is an irreversible inhibitor of complex II in the mitochondria. 3-NP toxicity has gained acceptance as an animal model of Huntington's disease (HD). In the present study, we confirmed that rats injected with 3-NP (20 mg/kg, i.p., daily for 4 days) exhibit increased oxidative stress in both striatum and cortical synaptosomes as well as lesions in the striatum. Synaptosomal membrane proteins from rats injected with 3-NP exhibited a decrease in W/S ratio, the relevant electron paramagnetic resonance (EPR) parameter used to determine levels of protein oxidation, and western blot analysis for protein carbonyls revealed direct evidence of increased synaptosomal protein oxidation. Treatment of rats with the brain-accessible free radical spin trap 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO; 30 mg/kg, i.p., daily 2 h before 3-NP injection) or with N-acetylcysteine (NAC; 100 mg/kg, i.p., daily 2 h before 3-NP injection), a known glutathione precursor, before 3-NP treatments protects against oxidative damage induced by 3-NP as measured by EPR and western blot analysis for protein carbonyls. Furthermore, both DEMPMPO and NAC treatments before 3-NP administration significantly reduce striatal lesion volumes. These data suggest oxidative damage is a prerequisite for striatal lesion formation and that antioxidant treatment may be a useful therapeutic strategy against 3-NP neurotoxicity and perhaps against HD as well.

Topics: Acetylcysteine; Animals; Antioxidants; Cerebral Cortex; Corpus Striatum; Cyclic N-Oxides; Electron Spin Resonance Spectroscopy; Glutathione; Huntington Disease; Male; Membrane Proteins; Nitro Compounds; Oxidative Stress; Propionates; Rats; Rats, Sprague-Dawley; Synaptic Membranes; Synaptosomes

Topics: Alkylation; Cyclic N-Oxides; Electron Spin Resonance Spectroscopy; Erythrocyte Membrane; Hemoglobin, Sickle; Hemoglobins; Humans; Huntington Disease; Membrane Proteins; Spherocytosis, Hereditary; Spin Labels; Sulfhydryl Compounds; Temperature