氯碘羟喹对β-淀粉样蛋白聚集影响的体外研究  

Effect of clioquinol on aggregation of β-amyloid in vitro

作　　者：李鑫[1] 黄晏[1] 胡增峣[1] 刘港[1] 周文霞[1] 张永祥[1] 

机构地区：[1]军事医学科学院毒物药物研究所,国家抗毒药物与毒理学重点实验室,北京100850

出　　处：《国际药学研究杂志》2014年第3期348-353,共6页Journal of International Pharmaceutical Research

基　　金：国家自然科学基金资助项目(81202505;81302759);国家"重大新药创制"科技重大专项资助项目(2012ZX09301003-002);国家科技支撑计划资助项目(2012BAI29B07)

摘　　要：目的考察氯碘羟喹(clioquinol,CQ)在体外对β-淀粉样蛋白(β-amyloid,Aβ)聚集的影响以及这种作用是否与金属离子Zn2+相关。方法采用硫黄素T(thioflavin,Th-T)结合实验检测聚集态Aβ;采用全波长吸收光谱扫描和竞争结合实验排除Th-T结合实验中可能存在的假阳性因素;采用圆二色谱检测Aβ的β-折叠。结果 CQ直接与单体态Aβ或聚集态Aβ共孵育24 h后均能明显降低Th-T的荧光强度;全波长吸收光谱扫描显示CQ在450 nm和485 nm附近均无特异性吸收峰;竞争结合实验表明,增加Th-T无法使体系的荧光强度恢复到最大;圆二色谱扫描结果表明,CQ可抑制Aβ的β折叠形成。CQ影响Aβ聚集的量效关系研究表明,单体态Aβ与CQ孵育时,其抑制Aβ聚集的IC50值在无Zn2+和含Zn2+体系中分别为6.1和4.3μmol/L;在已聚集的Aβ体系中,其解聚Aβ的IC50值在无Zn2+和含Zn2+体系中分别为7.5和6.1μmol/L。结论 CQ可直接抑制Aβ聚集,并使已聚集的Aβ解聚,且在pH为6.6条件下,实验体系中的Zn2+对CQ抗Aβ聚集的能力没有明显影响。Objective To study whether the metal chelator clioquinol （CQ） can affectβ-amyloid （Aβ） aggregation directly in vitro and whether this effect could be influenced by Zn2＋. Methods In the study thioflavin T （Th-T） fluorescence was used to detect the aggregated Aβ. To eliminate the possible false positive results, the absorption spectrum （300 nm to 600 nm） of CQ was scanned, and a competitive binding assay was applied to determine whether Th-T and CQ had the same binding site on Aβ. Circular dichroism spectroscopy was used to detect β-sheet formation of Aβ. Results CQ could decrease the fluorescence intensity, when incubated with monomer Aβor aggregated Aβfor 24 h. Absorption spectra indicated that CQ had no specific absorption peak at 450 nm and 485 nm. Competitive binding assay showed that CQ and Th-T did not bind the same site on Aβ. CD spectra showed that CQ could decrease theβ-sheet formation of Aβ. When incubated with monomer Aβ, CQ decreased the fluorescence intensity in a dose dependent manner, and the IC50 were 6.1μmol/L （without Zn2＋） and 4.3μmol/L （with Zn2＋）;When incubated with aggregated Aβ, CQ decreased the fluorescence intensity in a dose dependent mannerand, and the IC50 was 7.5μmol/L （without Zn2＋） and 6.1μmol/L （with Zn2＋）. Conclusion CQ can inhibit the aggregation of monomer Aβand depolymerize the aggregated Aβdirectly in vitro. Zn2＋has little influence on the effect of CQ on Aβ.

关 键 词：阿尔茨海默病 氯碘羟喹 Β-淀粉样蛋白 硫黄素T 

分 类 号：R749.16[医药卫生—神经病学与精神病学]