低温等离子体肝素化改性后小肠黏膜下层的血液相容性及其构建小口径血管的可行性

背景:栓塞是小口径血管植入后失败的主要原因,目前常常对血管支架材料进行抗凝改性,以期提高其血液相容性,从而提高血管的有效通畅性.目的:观察低温等离子体肝素化改性后的内植物修复材料小肠黏膜下层的血液相容性,并探讨其体内构建小口径血管的可行性.设计:单一样本实验.单位:上海交通大学附属第六人民医院骨科、上海市四肢显微外科研究所.材料:实验于2006-01/10在上海市四肢显微外科研究所实验室进行.小肠黏膜下层来自农场猪.方法:①改性:将猪小肠黏膜下层用氩等离子体处理器照射处理,氩气流量20mL/min,照射时间分别为0,2,4,6,8,10,12,14 s,接着浸入肝素钠溶液24 h.②体内抗凝血实验:将20条狗分为2组,分别植入经过改性或未改性的小肠黏膜下层缝合成的3 mm口径血管支架,与股动脉直接吻合,观察6周.主要观察指标:①血液相容性检测:通过扫描电镜观测表面形态,并通过液滴接触角、凝血时间及血小板黏附实验检测小肠黏膜下层改性前后的抗凝性.②体内抗凝血:通过彩色多普勒和组织学检测,评价血管支架直接在体内循环血流下的长期通畅性和形成血管的可行性.结果:①改性小肠黏膜下层膜表面呈现出均匀的微结构改变,随着等离子体照射时间增加,表面液滴接触角降低;改性后凝血酶原时间、活化部分凝血活酶时间和凝血酶时间延长:血小板黏附减少.②植入体内后未改性小肠黏膜下层血管支架3 d内栓塞,改性组在6周内仍保持通畅,管腔内表面有完整内皮细胞覆盖.结论:经低温等离子体肝素化改性后小肠黏膜下层的亲水性、抗凝性有明显提高.

Surface heparinization and blood compatibility modification of small intestinal submucosa for small-caliber vascular regeneration with hypothermic plasma technique

BACKGROUND:Thrombogenesis is the most common cause of failure in the implantation of tissue engineered small-caliber vesselgrafts.And immobilizing heparin onto the surfaces of vascular scaffoidgrafts is often applied to improve their blood compatibility and patency.OBJECTIVES:To investigate the small intestinal submucosa(SIS)surface after heparinizadon with hypothermic plasma technique,to ireprove the blood compatibility of SIS and to explore the possibility for the construction of small-caliber vascular grafts with modified SIS seaffolds in vivo.DESIGN:Single exponent study.SETTING:Department of Orthopaedics,the Six People's Hospital Affiliated to Shanghai Jiao Tong University;ShanghaiInstitute for Microsurgery of Extremities.MATERIALS:This study was performed in the Shahghai Institute for Microsurgery of Extremities from January to October 2006.The jejuna were taken from farm pigs.METHODS:The SIS surface of pigswere processed by argon plasma(20mL/min)technique at different time periods(0,2,4,6,8,10,12,and 14 s),which were then immediately immerged in heparin sodium solution for 24 hours.Dogs were divided into two groups.The SIS films were sewn into a 3-mm diameter tube and implanted into the defect of a canine femoral by anastomosis as a vascular graft.The observation lasted for 6 weeks.MAIN OUTCOME MEASURES:The surface morphologies of SIS were observed under scanning electron microscope(SEM).The antithrombogenicity of SIS films was tested by water contact angle,blood coagulation time and platelet adherence observation by SEM.The efficiency of the SIS graft was evaluated by the patency in the circulation of blood with colour doppler detection and histology.RESULTS:Heparinized SIS showed great different surface morphology comparing with untreated SIS.Untreated SIS surface looked like wrinkled film,but on heparinized SIS surface spread with uniform micro-dots,which looked like a layer of heparin adhesion.Water contact angle decreased with the increase of plasma irradiation time.Prothrombin time (PT),partial thromboplastin time(APTT),and thrombin time(TT)of the SIS films modified with heparin were prolonged.Platelets adhered much more on untreated SIS film than on heparinized SIS film.Vascular graft from SIS embolized in the lumina completely at day 3 after anastomosis.Heparinized SIS graft kept patency for six weeks,and the inner surface of graft was covered with full endothelial cells.CONCLUSION:Hydrophilicity and antithrombogenicity of heparinized SIS are increased obviously after hypothermia plasma treatment.