老年痴呆发病机制的研究:APP17肽对β-淀粉样肽导致神经元毒性作用的影响(英文)

Effect of APP 17-mer peptide on the neurotoxicity of beta-amyloid:a study on the pathogenesis of senile dementia

背景:老年斑是老年性痴呆(Alzheimer'sDisease,AD)的主要病理特征之一,以β-淀粉样肽(β-Amyloid,Aβ)沉积为核心,Aβ的神经元毒性定位于Aβ25-35。Aβ前体蛋白(β-amyloidproteinprecursor,APP)中319-335肽段即APP17肽(APP17-merpeptide),具有神经营养和神经保护作用。目的:通过观察APP17肽对Aβ引起神经毒性作用的影响,进一步证实此肽的神经营养作用,并为阐明AD的发病机制和临床治疗提供理论依据。设计:标准对照实验研究。地点和材料:本研究的地点为首都医科大学宣武医院神经生化研究室。SY5Y细胞株由瑞典卡罗琳斯卡研究所赠送,APP17肽和Aβ25-35由本室用固相法合成,高效液相纯化。方法:固相法合成APP17肽、Aβ25-35,高效液相纯化,以人神经母细胞瘤株SY5Y为细胞模型,分为正常对照组、Aβ25-3510μmol/L损伤组和Aβ25-3510μmol/L加APP17肽10μmol/L保护组。以细胞计数、噻唑蓝代谢率、乳酸脱氢酶漏出率、细胞轴突长度、胞体面积和细胞内游离钙离子(Ca2+)浓度为观察指标。结果:与正常对照组相比,Aβ25-35损伤组轴突长度(35.74±16.25)和胞体面积(495.92±87.68)均缩小,细胞计数接种后第6天犤(8.39±1.31)×107L-1犦减少,噻唑蓝代谢率降低,乳酸脱氢酶漏出率升高,细胞内游离钙离子浓度升高。

BACKGROUND:Senile plaque is one of the main pathological features in Alzheimer 's disease(AD).beta-amyloid(Aβ)deposition forms the core of senile plaques, an d Aβ25-35 is now recognized as a neurotoxic segment. Aβprotein precursor(APP) 319-335 segment(APP 17-mer peptide) has neurotrophic and neuro-protective ef fects. OBJECTIVE:To illustrate the effect of APP 17-mer peptide on the neurotoxicity of Aβ. DESIGN:A standard controlled study. SETTING and MATERIALS:The study was made in the Department of Neurobiochemisty ,Xuanwu Hospital of Capital University of Medical Sciences.SY5Y cell line is a g ift of Karolinska Institute in Sweden.APP 17-mer peptide and Aβ25-35 were syn thesized by means of solid phase method,and purified by high performance liquid chromatography(HPLC). METHODS:APP 17-mer peptide and Aβ25-35 were synthesized by solid phase meth od and purified by HPLC.Human neuroblastoma cells SY5Y were grouped into normal control group,Aβ25-35 damaged group and Aβ25-35+APP 17-mer peptide for neu roprotection group.Cell count,MTT metabolic rate,lactate dehydrogenase(LDH)lea kage rate, axonal length, area of cell body,and concentration of intracellular f ree calcium ion were used as indicators. RESULTS:Compared with the normal control group,Aβ25-35 reduced the cell coun t[on day 6 after inoculation,(8.39±1.31)×107 L-1]and MTT metabolic rate,incre ased LDH leakage rate,diminished the axonal length(35.74±16.25) and the area of cell body(495.92±87.68),and increased the concentration of intracellular free calcium ion,while the addition of APP 17-mer peptide normalized the foregoing c hanges. CONCLUSION:APP 17-mer peptide has neurotrophic and neuroprotective effect in alleviating the neurotoxicity of Aβ.