Hayashi Yoshihito, Ueda Yuto, Nakajima Akira, Mitsuyama Yoshio
Department of Psychiatry, Miyazaki Medical College, 5200 Kihara, Kiyotake-Cho, Miyazaki 889-1692, Japan.
Brain Res. 2004 Oct 29;1025(1-2):29-34. doi: 10.1016/j.brainres.2004.07.067.
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.
来自多个研究小组的最新数据表明，β-淀粉样蛋白（Aβ）神经毒性的主要机制可能由自由基介导。为了评估这一假说，我们的目标是明确Aβ神经毒性的机制，尤其是在自由基形成方面。在本研究中，将大鼠嗜铬细胞瘤（PC12）细胞暴露于Aβ25-35，并使用两种自旋捕获剂5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）和α-（4-吡啶基-1-氧化物）-N-叔丁基硝酮（POBN）来确认自由基的产生。DMPO自旋加合物显示存在羟基自由基（OH），而POBN自旋加合物则鉴定出脂质自由基（L），作为Aβ25-35暴露导致细胞损伤过程中脂质过氧化的电子顺磁共振（EPR）证据。还使用WST-8还原系统和组织化学分析进行了Aβ细胞毒性测定。这些分析表明Aβ可诱导细胞损伤。本研究提供了EPR证据，表明Aβ神经毒性源自羟基自由基从多不饱和脂肪酸中夺取氢，从而导致脂质过氧化。
