论文部分内容阅读
目的研究类叶升麻苷(Acteoside,AS)在体外对β-淀粉样蛋白片段(Aβ_(1-42))聚集的影响。方法采用硫黄素T(Th-T)结合实验研究各个浓度AS对单体态Aβ_(1-42)聚集的抑制作用以及对聚集态Aβ_(1-42)的解聚作用、呈现出的量效关系;通过对AS和AS+Th-T进行300~600nm全波长吸收光谱扫描以及(160、320、640μmol/L)AS与(1.25、2.5、5、10、20、40、80、160和320μmol/L)Th-T竞争结合实验,排除实验中可能存在的假阳性因素。结果硫黄素T结合实验表明,加入AS共同孵育24h后,单体态或聚集态Aβ_(1-42)的荧光强度均能减弱;全波长吸收光谱扫描显示在450nm和485nm处,AS、AS+Th-T均无特异性吸收峰,在450nm处给予刺激后,485nm附近也没有出现强的吸收;竞争结合实验表明,固定AS浓度,增加Th-T浓度,不会使荧光强度恢复至未加入AS组,则两者不存在相关结合位点;在AS影响Aβ_(1-42)聚集的量效关系实验中,AS抑制Aβ_(1-42)聚集的IC_(50)为254.3μmol/L,对聚集态Aβ_(1-42)解聚的IC_(50)为282μmol/L。结论 AS可有效抑制单体态Aβ_(1-42)的聚集,对聚集态的Aβ_(1-42)也有明显解聚作用,提示AS对老年痴呆具有潜在的治疗作用。
Objective To study the effect of Acteoside (AS) on the aggregation of β-amyloid fragment (Aβ 1-42) in vitro. Methods Thioflavin T (Th-T) binding assay was used to study the inhibitory effect of various concentrations of AS on the aggregation of monomeric Aβ 1-42 and the depolymerization of aggregated Aβ 1-42. The dose-response relationship (AS), AS + Th-T (300-600 nm full-wavelength absorption spectra) and (160,320,640 μmol / L) AS and (1.25,2.5,5,10,20,40,80,160 and 320μmol / L) Th-T competition binding experiment to exclude possible false positive factors in the experiment. Results Thioflavin T binding assay showed that the fluorescence intensity of monomeric or aggregated Aβ 1-42 could be weakened after incubation with AS for 24 h. At 450 nm and 485 nm, the absorbance spectra of AS, AS + Th -T showed no specific absorption peak. No strong absorption near 485 nm was observed after stimulating at 450 nm. The competitive binding assay showed that the concentration of fixed AS and the increase of Th-T concentration did not restore the fluorescence intensity to that of the non-added AS Group, there was no related binding sites between them. In the dose-effect relationship experiment in which AS affected the aggregation of Aβ 1-42, the IC 50 of AS inhibiting Aβ 1-42 accumulation was 254.3 μmol / L, IC 50 of depolymerized Aβ 1-42 was 282 μmol / L. Conclusions AS can effectively inhibit the aggregation of monomeric Aβ 1-42 and depolymerize the aggregated Aβ 1-42, suggesting that AS may have a potential therapeutic effect on Alzheimer’s disease.