聚甲基丙烯酸丁酯／纳米二氧化硅涂层支架的生物相容性研究

目的评价不锈钢支架聚甲基丙烯酸丁酯，纳米二氧化硅涂层的生物相容性。方法聚甲基丙烯酸丁酯，纳米二氧化硅涂层支架与裸金属支架分别置入犬冠状动脉回旋支，每组9只，术后4周时行冠状动脉造影及组织病理学分析，涂层组支架置入前与置入后4周采集血清样本做肝肾功能检测。结果两组犬4周时冠状动脉造影显示支架段管腔狭窄，无血栓形成、栓塞及动脉瘤，光学纤维镜下未见内膜下出血和中层坏死，无附壁血栓，无明显炎症细胞浸润；扫描电子纤维镜显示所有支架段血管基本内皮化，管壁无血小板和纤维蛋白沉积。两组犬损伤积分差异无统计学意义（P〉0．05），新生内膜厚度、管腔面积、管腔面积狭窄率及内膜平滑肌细胞百分率比较差异无统计学意义（P〉0．05），涂层支架置入后与置入前比较对肝肾功能无明显影响（P〉0．05）。结论不锈钢支架聚甲基丙烯酸丁酯，纳米二氧化硅涂层具有良好的生物相容性，不引起严重的局部组织反应，可用于药物洗脱支架的制作。

The biocompatibility of polybutyl methacrylate/nano silica coated stainless steel stents

Objective To evaluate the biocompatibility of polybutyl methacrylate/nano silica coated stainless steel stents in a canine coronary artery model. Methods Bare stents and polybutyl methacrylate/nano silica coated stents were implanted with mild oversizing in left circumflex coronary arteries of 18 canines and evaluated by angiography, light and scanning electron microscopy after 4 weeks.The analysis on hepatic and renal function was made before the coating stents implantation and at the end point. Results No intraintimal hemorrhage, no medial and adventitial necrosis, no aneurysm, thrombosis or inflammatory cells infiltration occurred on any stent.Complete re-endothelialization was seen in both stent types. The mean injury scores, neointimal thickness, luminal area, degree of stenosis and percentage of neointimal smooth muscle cells were similar between bare stents group and coating stents group （P〉0.05）. The changes of alanine aminotmnsferase （ALT）, aspartate aminotransferase （AST）, alkaline phosphatase（ALP）, blood urea nitrogen （BUN） and creatinine （Cr） before or after coating stents implantation showed no significant difference （P〉0.05）. Conclusion The polybutyl methacrylate/nano silica coated stainless steel stent has good biocompatibitity and can be used for drug eluting stent.