CD^34＋细胞与单个核细胞对新型小口径人工血管早期抗血栓形成影响的比较

Comparison of the antithrombogenic property between CD34 positive cells and unfractioned mononuclear cells seeded on small caliber man-made vascular grafts

目的比较纯化的CD^34＋细胞与未经筛选的单个核细胞（uMNCs）作为种子细胞在小口径组织工程血管早期的抗凝作用。方法uMNCs与CD^34＋细胞分离自犬骨髓，将两种细胞分别在体外培养、传代，内皮细胞生长因子诱导分化，体外血小板黏附实验检测细胞的体外抗血小板黏附功能。将等量自体上述两种细胞分别种植在小口径人造血管腔内表面并替代一段颈动脉。分别在24h、72h、1周后取出移植血管行苏木素-伊红（HE）染色和扫描电镜检查。结果体外血小板黏附实验显示CD^34＋细胞抗血小板聚集作用显著高于uMNCs。植人体内后，移植uMNCs血管腔表面比种植CD^34＋细胞的有更多的血小板黏附和血栓形成。24h、1周后CD^34＋细胞组血栓面积与移植的血管腔表面积之比小于uMNCs组，差异有统计学意义（P〈0．05）。结论CD^34＋作为种子细胞种植小口径人工血管后比未经筛选的uMNCs具有更好的早期抗血栓形成功能。

Objective To compare the antithrombogenic property of purified CD^34＋ cells with that of unfractioned mononuclear ceils （uMNCs） after seeding on the small caliber man-made grafts. Methods uMNCs and CD^34＋ cells were isolated from the canine bone marrow. Platelet adhesion assay was performed to determine antiplatelet adhesion property of the cells in vitro. Equal number of both cells were seeded onto the luminal surface of small caliber man-made grafts and implanted to replace a segment of common ca- rotid artery. At time intervals of 24 h, 72 h, and 1 week, the grafts were retreived, HE staining and scanning election microscopy （SEM） exam were performed. Results Platelet adhesion assay indicated that there was more significant platelet adhesion on uMNCs than that on CD^34＋ cells. SEM revealed that there was more significant platelet adhesion and thrombus formation on the luminal surface of the grafts seeded with uMNCs than those seeded with CD^34＋ cells 24 h after implantation. The ratio of thrombi area to the luminal surface area of grafts in CD^34＋ cells group at 24 h and 1 week was statistically lower than that of the uMNCs group （P 〈 0. 05）. Conclusion CD^34＋ cells exhibit better antithrombogenic ability after seeding onto the small caliber vessel grafts as compared with uMNCs. CD^34＋ cells may be preferable cell source for better improve the thromboresistance and patency of small caliber man-made vessel grafts for their future clinical application.