EPR evidence of hydroxyl radical generation as an initiator of lipid peroxidation in amyloid beta-protein-stimulated PC12 cells.
Recent data from several groups suggest that the primary mechanism of amyloid beta-protein (Abeta) neurotoxicity may be mediated by free radicals. To evaluate this hypothesis, our aim is to make the mechanism of Abeta neurotoxicity clear, especially in the formation of free radicals. In this study, rat pheochromocytoma (PC12) cells were exposed to Abeta25-35 and confirmed free radical generations using two kinds of spin trap agents, 5,5-dimethyl-1-pyrroline-N-oxide; DMPO and alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone; POBN. DMPO spin adduct revealed that hydroxyl radical (OH), while POBN spin adduct identified a lipid radical (L) as electron paramagnetic resonance (EPR) evidence of lipid peroxidation in the process of cell damage by Abeta25-35 exposure. An Abeta cytotoxicity assay also was performed by using WST-8 reduction system and histochemical analysis. These analyses showed cell damage induced by Abeta. This study provides EPR evidence that Abeta neurotoxicity is derived from hydrogen abstraction from polyunsaturated lipid acid by hydroxyl radical as a cause of lipid peroxidation.
Hayashi
Yoshihito
Y
Department of Psychiatry, Miyazaki Medical College, 5200 Kihara, Kiyotake-Cho, Miyazaki 889-1692, Japan. yoshih@med.miyazaki-u.ac.jp
Ueda
Yuto
Y
Nakajima
Akira
A
Mitsuyama
Yoshio
Y
D016229:Amyloid beta-Peptides / Q000494:pharmacology* / Q000633:toxicity; D000818:Animals; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D017665:Hydroxyl Radical / Q000378:metabolism* / Q000633:toxicity; D015227:Lipid Peroxidation / Q000502:physiology*; D016716:PC12 Cells; D010446:Peptide Fragments / Q000494:pharmacology* / Q000633:toxicity; D051381:Rats
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C074636:amyloid beta-protein (25-35); D017665:Hydroxyl Radical