Shearman M S, Ragan C I, Iversen L L
Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, United Kingdom.
Proc Natl Acad Sci U S A. 1994 Feb 15;91(4):1470-4. doi: 10.1073/pnas.91.4.1470.
An in vitro tissue culture cell model system for investigating the biochemical mechanisms involved in the neurodegenerative actions of beta-amyloid has been established. Using rat pheochromocytoma PC12 cells, it was found that an early, specific response of cells to the beta-amyloid protein or the beta-amyloid fragment 25-35 was a potent inhibition of cellular redox activity, as measured by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) reduction. This inhibitory response was rapid and occurred at nanomolar concentrations of peptide, concentrations at which no equivalent decreases in cell proliferation or cell survival were observed. The inhibition of PC12 cell MTT reduction was initially reversible upon removal of the peptide; if sustained for several days, however, by repeated peptide application, it became associated with a dramatic reduction in cell survival. Inhibition of MTT reduction may, therefore, be an early indicator of the mechanism of beta-amyloid-mediated cell death.
已建立一种体外组织培养细胞模型系统，用于研究β-淀粉样蛋白神经退行性作用所涉及的生化机制。使用大鼠嗜铬细胞瘤PC12细胞发现，细胞对β-淀粉样蛋白或β-淀粉样蛋白片段25-35的早期特异性反应是对细胞氧化还原活性的有效抑制，这通过3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四氮唑溴盐（MTT）还原测定。这种抑制反应迅速，在纳摩尔浓度的肽时就会发生，在该浓度下未观察到细胞增殖或细胞存活有同等程度的降低。去除肽后，PC12细胞MTT还原的抑制最初是可逆的；然而，如果通过重复应用肽持续数天，它就会与细胞存活率的显著降低相关。因此，MTT还原的抑制可能是β-淀粉样蛋白介导的细胞死亡机制的早期指标。
