中文摘要：

目的研究β-淀粉样肽对人SH-SY5Y神经母细胞瘤细胞膜性脂质和胆碱能受体的影响及其意义。方法选择不同浓度B一淀粉样肽。处理SH—SY5Y细胞，用比色法测定细胞四甲基偶氮唑盐（MTT）还原率、脂质过氧化产物（丙二醛）、蛋白氧化产物（蛋白羰基）及磷脂含量，高效液相色谱法测定细胞胆固醇及辅酶Q水平，放射性配体一受体结合实验测定胆碱能受体．配体结合率，Western印迹方法测定细胞膜神经型尼古丁受体亚单位α3及α7蛋白表达水平，并对照研究维生素E的抗氧化作用。结果用低浓度（0．1μmol／L）β-淀粉样肽处理细胞后即出现MTT还原率和磷脂水平的下降，丙二醛及蛋白羰基水平升高，用较高浓度（1μmol／L）β-淀粉样肽处理细胞后胆碱能受体．配体结合密度、尼古丁受体亚单位α3，胡蛋白水平及辅酶Q含量降低，但未引起细胞胆固醇含量的改变。维生素E能明显对抗B-淀粉样肽的细胞毒性作用。结论β-淀粉样肽引起细胞膜脂质成分改变以及胆碱能受体水平降低，这些改变可能与其诱导的氧化应激增强有关。

英文摘要：

Objective To study the effects of β-amyloid peptide （Aβ） on cell membrane lipids and cholinergic receptors of human neuroblastoma cells. Methods Human SH-SYSY neuroblastoma cells were treated with different concentrations of Aβ1-42 with and without pretreatment of vitamin E. MTY [ 3-（ 4,5- dimethylthiazol-2-yl）-2,5-diphenyhetrazolium bromide] reduction, lipid peroxidation, protein oxidation and phospholipids were measured by spectrophotometry. Levels of cholesterol and unbiquinone were determined by high-performance liquid chromatography （HPLC）. The numbers of cholinergic receptor binding sites were determined by receptor binding assay and the protein levels of nicotinic receptor α3 and α7 subunits were studied by Western blotting. Results SH-SYSY cells showed decreased reduction rates of MMT and phospholipids, and increased lipid peroxidation and protein oxidation after exposure to Aβ （0.1 μmol/L） as compared to the control. The number of cholinergic receptor binding sites, the protein level of nicotinic receptor α3 and α7 subunits and the content of ubiquinone decreased in cells treated with high dose of Aβ （1 μmol/L）. Although the level of cholesterol was not changed in any way, vitamin E partially prevented the neurotoxic effects of Aβ. Conclusion β-amyloid peptide reduces the level of cell membrane lipids and cholinergic receptors in human SH-SYSY neuroblastoma cells, likely through the induction of an enhanced oxidative stress.