一种体外评价生物材料血栓形成的新方法

A new method for evaluating the thrombus formation on biomaterials in vitro

背景：心血管支架以及其他与血液接触的材料已得到迅速发展，但目前还没有一种统一的血栓评价方法来评价这些材料的血栓形成情况。目的：观察纤维蛋白原浓度与血栓形成的关系，拟建立一种新的体外评价生物材料血栓形成的方法。设计、时间及地点：材料学对照观察，于2007—12／2008-08在中国药品生物制品检定所医疗器械检测中心完成。材料：清洁级日本大耳白兔1只，普通玻璃为盐城荣康玻璃器材有限公司产品，医用硅橡胶和医用聚乙烯为天津塑料制品研究所产品。方法：采集兔心脏血，以38g／L枸橼酸钠部分抗凝，然后每隔3min向部分抗凝的血液中加入枸橼酸钠进行全抗凝，分离血浆，检测血浆中剩余纤维蛋白原的含量。同法制备部分抗凝血，分为阳性组、硅橡胶组、聚乙烯组、阴性对照组，前3组分别将硅化玻璃管中的部分抗凝血与玻璃、硅橡胶、聚乙烯接触，阴性对照组管中不加入任何物质，15min后向各管中加入枸橼酸钠进行全抗凝，分离血浆，检测血浆中剩余纤维蛋白原的水平。主要观察指标：纤维蛋白原质量浓度与血栓形成量的关系，比较硅橡胶、聚乙烯与玻璃的血栓形成程度。结果：随着部分抗凝血液在体外暴露时间的延长，血栓形成量逐渐增多，抗凝剂加入越晚，剩余血浆纤维蛋白原质量浓度就越低，表明纤维蛋白原量与血栓形成量成反比。与阳性组比较，聚乙烯组、硅橡胶组、阴性对照组纤维蛋白原平均质量浓度均明显升高（t=2．842～3．737，P〈0．05）；聚乙烯组、硅橡胶组纤维蛋白原平均质量浓度基本相似（t=0．747，P〉0．05），但两者均小于阴性对照组（t=3．691，3．192，P〈0．05）。结论：纤维蛋白原法可以作为评价生物材料血栓形成的初筛实验，用聚乙烯、硅橡胶和玻璃对该法进行了评价验证，结果显示硅橡胶和聚乙烯明显好于玻璃。

BACKGROUND： Cardiovascular stents and some materials contacted with blood have been developing rapidly. However, there is not a uniform method to evaluate the thrombosis of biomaterials at present. OBJECTIVE： To observe the relationship between the concentration of fibrinogen and thrombosis, and establish a new method for evaluating the thrombus formation on biomaterials in vitro. DESIGN, TIME AND SETTING： A control observational experiment of material science was performed in the Testing Center for Medical Device of National Institute for the Control of Pharmaceutical and Biological Product from December 2007 to July 2008. MATERIALS： One healthy Japanese rabbit, clean grade and weighing 2.5 kg, was used in the experiment. Glass was the product of Yancheng Rongkang Glassware CO., LTD.. Medical silicone rubber and polyethylene were the products of Tianjin plastic research institute. METHODS： Blood samples were drawn from the heart of rabbit with 3.8% sodium citrate for partial anticoagulation. Then, a part of sodium citrate was added into the partial anticoagulation blood for complete anticoagulation every 3 minutes. The concentration of fibrinogen was measured in plasma after separation. The blood samples of partial anticoagulation obtained with the same method as above were divided into four groups： positive, silicone rubber, polyethylene and negative groups. In the positive, silicone rubber, polyethylene groups, the blood samples of partial anticoagulation were contracted with glass, silicone rubber and polyethylene, respectively. The blood samples in the negative group were not contracted with anything. Fifteen minutes later, the sodium citrate was added in the four groups for complete anticoagulation. The concentration of fibrinogen was measured in plasma after separation. MAIN OUTCOME MEASURES： The relationship between concentration of fibrinogen and thrombosis were observed. And the extents of thrombus formation in the positive, silicone rubber, polyethylene groups were compared. RESULTS： With the increase of exposure time of the partial anticoagulation blood in vitro, the amount of thrombus formation increased gradually. The later the anticoagulant was added, the lower the concentration of fibrinogen was. The results suggested that the concentration of fihrinogen was inversely proportional to the amount of thrombosis. The concentrations of fibrinogen in the negative, silicone rubber, polyethylene groups were significantly higher than that in the positive group （t =2.842-3.737, P 〈 0.05）. There was no significant difference in concentrations of fibrinogen between the silicone rubber and polyethylene groups （t=0.747, P 〉 0.05）, but the concentrations of fibrinogen in both of them were significantly lower than that in the negative group （t =3.691, 3.192, P 〈 0.05）. CONCLUSION： The measurement of fibrinogen concentrations can be used as a screen test for evaluation of thrombus formation on biomaterials, which is proved by glass, polyethylene and silicone rubber. The findings show that the blood compatibility of silicone rubber and polyethylene is better than glass.