文章摘要

粉末冶金注射成型技术制备的新型血管内支架的动物应用研究

作者: 1,2舒畅, 1蔡文武, 1何昊, 1王暾, 3娄嘉, 4李益民
1 中南大学湘雅二医院 血管外科,湖南 长沙 410011
2 中国医学科学院阜外医院 血管外科,北京 100037
3 湘潭大学材料科学与工程学院,湖南 湘潭 411005
4 中南大学粉末冶金国家重点实验室,湖南 长沙 410083
通讯: 舒畅 Email: changshu01@yahoo.com
李益民 Email: liyimin333@163.com
DOI: 10.3978/.10.3978/j.issn.1005-6947.2017.02.012

摘要

目的:通过动物实验评估一种新型血管内支架临床应用的可行性和安全性。方法:将30枚粉末冶金注射成型技术制备新型血管内支架分别植入30只实验犬主动脉内,术后CT血管造影了解其在主动脉内情况,并通过大体肉眼观察、光镜、电镜及免疫组化了解内术后不同时间支架表面新生内膜情况。结果:所有支架均成功植入实验犬主动脉内。术后支架通畅率100%,无支架移位、扭曲、断裂,无支架感染及血栓形成,管腔无狭窄或闭塞;支架的轴向回缩率均<2%,径向回缩率均<4%。术后1周,支架腔面迅速被一薄层半透明膜状结构覆盖;术后1个月,支架绝大部分表面可见与周围血管正常内膜相延续的新生内膜;术后2个月,新生内膜基本上完整覆盖整个支架腔面(98.83%),其厚度达到峰值(350.00 μm);术后3~6个月,新生内膜厚度逐渐降低,管腔内径逐渐增大至植入前大小,最后新生内膜表面被单层完全成熟的内皮细胞覆盖。除术后1周外,其余时间点支架表面新生内膜组织中血管平滑肌细胞α-肌动蛋白染色均呈阳性,而各时间点支架腔面新生内膜组织中血管内皮生长因子染色均呈阳性。结论:粉末冶金注射成型技术制备的新型血管内支架植入后实验犬体内后形态结构稳定,并可迅速完成支架腔面内皮化,保持长期的通畅性,表现出良好的结构及理化稳定性和生物相容性,具有很好的临床应用前景。
关键词: 支架 材料试验 内皮细胞

Application of a novel intravascular stent prepared by metal powder injection molding in animals

Authors: 1,2SHU Chang, 1CAI Wenwu, 1HE Hao, 1WANG Tun, 3LOU Jia, 4LI Yimin
1 Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha 410011, China
2 Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100037, China
3 School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411005, China
4 State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China

CorrespondingAuthor:SHU Chang Email: changshu01@yahoo.com

Abstract

Objective: To assess the feasibility and safety of using a novel intravascular stent in clinical practice through animal experiment. Methods: Thirty intravascular stents prepared by metal powder injection molding were implanted into the aorta of 30 experimental dogs, respectively. After implantation, the intra-aortic conditions were observed by computed tomography angiography, and the neointimal formations on the stent surface at different postoperative times were observed by gross visual inspection and microscopic and electron microscopic evaluation as well as immunohistochemical staining. Results: All intravascular stents were successfully implanted into the aorta of the dogs. All stents were patent without any evidence of stent displacement, distortion or fracture and intrastent infection or thrombosis as well as intraluminal stenosis or occlusion; the longitudinal and radial shrinkage rates of the stents were less than 2% and 4%, respectively. At one week after implantation, the luminal surface of the stent was rapidly covered by a thin layer of semi-transparent membrane-like structure; at one month after implantation, neointimal formations were seen on most of the luminal surface of the stent which connected with the surrounding intima; at 2 months after implantation, nearly the complete luminal surface of the stent (98.83%) was covered by the neointima, and its thickness reached a peak value (350.00 μm); at 3 to 6 months after implantation, the thickness of the neointima was gradually reduced, its inside diameter was gradually increased to almost the initial size before implantation, and finally, the neointimal surface was covered by a single layer of fully mature endothelial cells. In the neointimal tissues on the luminal surface of the stent, positive staining of smooth muscle α-actin was detected at each time point except one week after immplantaion, while positive staining of vascular endothelial growth factor was detected at any time point after immplantaion. Conclusion: The novel intravascular stent prepared by metal powder injection molding can maintain stable form and structure with fast endothelialization of the luminal surface of stent, and keep long-term patency. It shows favorable structural, physical and chemical stability and biocompatibility, and may have a promising application prospect in clinical practice.
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