流体剪应力调节内皮化小径聚氨酯人工血管抗血栓特性的体外研究

研究不同流体剪应力条件下,内皮化小径聚氨酯人工血管分泌一氧化氮(Nitrogen monoxide, NO)和前列环素(Prostaglandin I2, PGI2)水平的变化,从而为剪应力处理调节内皮化小径聚氨酯人工血管抗血栓特性提供实验依据.分离健康成人外周血的单个核细胞并诱导分化成内皮祖细胞,通过相差显微镜和免疫荧光标记等方法对诱导分化后的细胞进行形态学观察和鉴定.种植内皮祖细胞到小径聚氨酯人工血管表面后,将内皮化小径聚氨酯人工血管分为静态组、低剪应力组(5 dynes/cm2)、中剪应力组(15 dynes/cm2)和高剪应力组(25 dynes/cm2)4个不同处理组,之后用硝酸还原酶法和酶联免疫吸附法测定不同时间点培养液中NO和6-keto-PGF1α(6-keto-prostaglandin F1α,6-keto-PGF1α)的水平.外周血单个核细胞分化成为内皮祖细胞,倒置荧光显微镜下呈典型的"纺锤样"梭形细胞, ac-LDL吞噬及lectin抗体荧光标记双阳性,FLK-1和vWF免疫荧光抗体染色均为阳性.流体剪应力增加种植人工血管表面内皮祖细胞NO和6-keto-PGF1α的产生,并且这种作用与剪应力大小呈正相关.因此,提高流体剪应力明显促进内皮祖细胞NO和PGI2等抗血栓物质的分泌,提示流体剪应力可改善内皮化小径聚氨酯人工血管抗血栓特性.

In Vitro Study of Regulation of Shear Stress on Antithrombogenic Potentials of Endothelialized Polyurethane Small Diameter Artificial Blood Vessel

This study was designed to investigate the changes of prostaglandin I2 (PGI2) and nitric oxide (NO) secreted by endothelialized polyurethane small diameter artificial blood vessel. The peripheral blood mononuclear cells of healthy adult were separated and induced into endothelial progenitor cells (EPCs), which were identified by the methods of discrepancy microphage and fluorescent immunology labeling. After the induced cells being seeded on the polyurethane small-diameter artificial vessels, the endothelialized polyurethane small diameter artificial blood vessels were divided into four different experimental groups, including stationary group, low-flow shear stress group (5 dynes/cm2), medium-flow shearstress group (15 dynes/cm2), and high-flow shear stress group (25 dynes/cm2). Then, the levels of 6-ketoprostaglandin F1alpha (6-keto-PGF1alpha) and NO of different time were measured by enzyme-linked immunosorbent assay and nitrate reductase methods. The peripheral blood mononuclear cells differentiated into EPCs. They presented typical "spindie-shaped" appearance, and they were positively labeled by fluorescent acetylated-LDL, lectin, FLK-1 and vWF. Shear stress enhanced the production of NO and 6-keto-PGF1alpha by EPCs in a dose-dependent manner. Therefore, shear stress increases the secretion of NO and PGI2 by EPC, which suggests that shear stress can improve the antithrombogenic potentials of endothelialized polyurethane small diameter artificial blood vessel.