人血浆低密度脂蛋白分离鉴定及粒径测定

Seperatation and identification of human low density lipoprotein and determination of particle size

目的对特异性沉淀法提取人血浆中低密度脂蛋白(LDL)进行优化,并用一种新手段来表征LDL粒径大小。方法用柠檬酸钠-肝素钠缓冲液特异性沉淀人血浆中LDL;用高分辨率Zeta电位及粒度分析仪测定LDL粒径,用透射电镜(TEM)观察LDL的外观形态,并与超速离心法分离得到的LDL的粒径及外观形态进行对比。结果用沉淀法分离得到电泳纯级LDL;沉淀法分离得到的LDL粒径为(31.7±1.1)nm,超速离心法分离得到LDL粒径为(32.9±0.8)nm,差异无统计学意义(t=2.00,P>0.05);两法分离的LDL形态相似,均为类圆形。结论与超速离心法分离LDL相比,沉淀法是一种简单快速的提取LDL的方法,且纯度较高;用高分辨率Zeta电位及粒度分析仪测定LDL粒径简单、快捷、成本较低。

Objective：To optimize specific precipitation method for separating low density lipoprotein （LDL） from human plasma, and develop a new method to characterize the LDL particle size. Methods：LDL was rapidly precipitated from human plasma by using heparin citrate buffer. The size of LDL particles was determined by Zeta potential with high resolution and nanoparticle size analyzer. The morphologic appearance of the particle was observed by transmission electron microscopy. The size and shape of the particle were compared with those separated by ultracentrifugation. Results：The purity of LDL separated by either precipitation or ultracentrifugation method achieved electrophoresis level since the electrophoresis showed only one band of LDL The sizes of LDL separated by heparin citrate buffer precipitation and ultracentrifugation were （31.7±1.1） and （32.9±0.8） nm respectively and no statistical difference was found. The roundish shapes of LDL particle separated by both methods were similar. Conclusion：Compared with the ultracentrifugation, heparin citrate buffer precipitation method was easily and rapid for separating LDL with high purity. The determination for LDL particle size by Zeta potential with high resolution and nanoparticle size analyzer was simple and cost-saving.