摘要
目的观察淀粉样蛋白25～35片段(Aβ25～35)对二磷酸腺苷诱导的血小板聚集及血小板胞质内钙离子水平的影响,探讨淀粉样蛋白在血小板中的作用。方法采集18例健康志愿者肘静脉血,检测在不同浓度Aβ25～35(0、5、10、20、40μmol/L)的作用下二磷酸腺苷诱导的血小板最大聚集率(PAGMax);以50%最大聚集反应的二磷酸腺苷浓度(EC50)1μmol/L作为测定Aβ25～35对血小板聚集影响的二磷酸腺苷基础浓度;激光共聚焦显微镜检测不同浓度Aβ25～35作用下钙荧光探针Fluo-3/AM标记的血小板胞质内钙离子([Ca2+]i)变化。结果(1)于富血小板血浆中加入二磷酸腺苷后,以二磷酸腺苷浓度为1μmol/L时血小板EC50最高,为(26.33±6.57)%,故以此作为测定Aβ25～35影响血小板聚集功能的基础浓度。(2)Aβ25～35作用前后,二磷酸腺苷诱导的PAGMax均不同程度增高(P<0.05),且随着Aβ25～35浓度增加,血小板最大聚集率呈逐渐增加(P<0.05),其中以40μmol/L浓度组血小板聚集率最大,与单纯给予二磷酸腺苷(Aβ25～35为0μmol/L时)相比差异具有显著性意义(P<0.01)。(3)不同浓度Aβ25～35(0、5、10、20、40μmol/L)诱导后,血小板胞质内[Ca2+]i水平均不同程度升高(P<0.01),[Ca2+]i浓度平均增高水平随Aβ25～35浓度的增加而增加(P<0.01),其中以40μmol/L浓度组血小板胞质内[Ca2+]i水平升高最为显著(P<0.01)。结论较高浓度的Aβ25～35具有促进二磷酸腺苷诱导血小板聚集、升高血小板胞质内[Ca2+]i水平的作用,Aβ25～35促进血小板聚集的作用可能与血小板胞质内钙离子水平的升高有关。
Objective To observe the effect of amyloid fragment 25-35 （Aβ25-35） on ADP induced platelet aggregation and intracytoplasmic calcium of platelet for studing the action of amyloid on plalelet. Methods The venous blood of 18 healthy volumteers was adopted and determined the maximal aggregating rate of platelet （PAGmax） induced by adding different concentration of ADP in various level of Aβ25-35 （0, 5, 10, 20, 40μLmol/L）. The basal concentration of ADP for affecting platelet aggregation by amyloid was defined as 1μmol/L （EC50 the concentration of ADP for 50% maximal platelet aggregation）. The alteration of intracytoplasmic Ca^2＋ （[Ca^2＋]i） labelled by fluoresent calcium probe Fluo-3/AM was determined by different concentration of amyloid under confocal scanning microscope. Results 1） Adding ADP into platelet rich plasma, the maximum of EC50 （26.33±6.57）% was obtained when concentration of ADP was 1μmol/L, thus it was defined as the basal ADP concentration in determing the Aβ25-35 for affecting platelet aggregation. 2） The ADP induced PAGmax increased in different extent before and after the action of Aβ25-35. The maximal platelet aggregation rate was gradually increased as the increasing concentration of Aβ25-35 （P 〈 0.05）. The highest platelet aggregation rate occurred in the group of 40μmol/L Aβ25-35. The difference was significant （P 〈 0.01） compared with adding ADP only （0mol/L Aβ25-35）. 3） The platelet intracytoplasmic [Ca^2＋]i concentration increased after inducing by Aβ25-35 and its increasing level was according to the concentration of Aβ25-35. The most significant increasing level of platelet [Ca^2＋]i （P 〈 0.01） established when existing 40 0644mol/L Aβ25-35 Conclusion The effect of higher concentration of Aβ25-35 may promote ADP induced platelet aggregation and -increases platelet （[Ca^2＋]i） concentraion. It shows that the promoting effect of Aβ25-35 on platelet aggregation might be associated with the increasing level of platelet intracytoplasmic Ca^2＋ level.
出处
《中国现代神经疾病杂志》
CAS
2006年第2期124-127,共4页
Chinese Journal of Contemporary Neurology and Neurosurgery
基金
国家自然科学基金资助项目(30370494)
关键词
阿尔茨海默病
淀粉样Β蛋白
血小板聚集
钙
Alzheimer disease Am.yloid beta-protein Platelet aggregation Calcium
