【作者】 魏清荣；

【导师】 万昌秀；

【作者基本信息】 四川大学 ， 生物医学工程， 2003， 硕士

【摘要】 牛心包是一种以Ⅰ型胶原为主要成分，具有良好机械力学性能的天然生物材料。在传统应用中，牛心包材料大多作为不可降解材料而用于生物心脏瓣膜、人工血管及修补材料等。为了充分发掘牛心包这种天然生物材料的潜力，利用其固有优势，拓宽其应用范围，本文的研究是国家自然科学基金项目：“心包材料表面修饰诱导组织再生及控制降解机理的研究”的一部分。首次从牛心包作为可降解型天然生物材料的角度，研究了控制牛心包材料降解速率的化学改性方法，比较了几种改性牛心包材料的体内外降解规律，探讨了降解速率符合组织工程要求的改性心包材料的细胞相容性、免疫原性及对组织液成分的通透性等。 在改性处理牛心包的方法上，围绕改变心包的生物降解速率，本文分别用环氧交联剂、戊二醛、碱与胰酶等方法处理心包。研究结果表明，几种改性牛心包在体外的降解速率的顺序为：环氧交联心包(EPBP)＜戊二醛交联心包(GABP)＜未改性心包(UMBP)＜促降解处理心包(DFBP，碱与胰酶处理心包)。DFBP在动物体内埋植3个月后的降解失重率接近90％，能够满足组织工程对可降解生物支架材料的要求；相对UMBP而言，由于去除了心包上的残余细胞等抗原成分，DFBP的免疫原性明显降低；组织学观察也证实DFBP上的残余细胞及细胞碎片被完全除去，并且胶原纤维得到疏松；细胞培养显示，内 四川大学硕士学位论文皮细胞能够粘附在DFBP的光滑面上，细胞形态由椭圆形、圆形伸展成梭形、多角形;细胞之间有明显的连接;能够分泌特异性的生物活性因子一一内皮素。层粘连蛋白能够进一步提高DFBP的细胞相容性。此外，DFBP对营养成分的通透性也较之于UMBP得到改善，对白蛋白、葡萄糖的筛分系数分别达90%和60%以上，具备和周围的组织环境进行物质交换的可能。 研究中还尝试将改性后的牛心包做成神经导引管用以修复受损的周围神经。术后两个月于导管远端检测到坐骨神经动作电位和胖肠肌动作电位，说明牛心包材料具有引导组织再生的潜力。 本文的研究为牛心包材料在人工皮肤、人工血管等软组织的组织工程支架材料领域的开发和应用作了较为全面的基础性探索。更多还原

【Abstract】 Bovine pericardium(BP) is a kind of natural biomaterial which is mainly composed of type I collagen. Up to the present, BP is usually utilized as valve , artificial vein, repairing-material and so on for its appropriate mechanical property. However, in this paper, EP is firstly studied for degradable biomaterial. Modifying methods used to control the degradation of BP were discussed; The degradation behavior of several modified BP were investigated and compared; Based on these studies, cell-compatibility , immunogenicity and permeability of DFBP were investigated.BP was cross-linked by EP and GA respectively, which resulted in prolonged degradation; Accelerated degradation was obtained through Ca(OH)2 and trypsin processing. Ca(OH)2 could separate and swell collagen fibre; Trypsin not only could loosen fibre , but also digested the components of antigen on BP. Studies of the degradative performance of several modified BP in vitro indicated the sequence of their degradation rate: EPBP<GABP<UMBP<DFBP. Weight-loss of DFBP in vivo had come to 90% by three months, while the one of UMBP less than 80%. Light micrographs of tissue section of DFBP showed that the collagen fibre was well loosened , and that components such as cell remained , cellular debris were mostly gotten rid of. The immunogenicity of DFBP had been greatly reduced. In addition, the permeability of DFBP had been improved.Experiment of endotheliocyte(EC) cultivation suggested that BP has a certain cellular affinity, and that the cell-compatibility of LCDFBP had been improved evidently: the shape of EC from rotundity changed to shuttle or polygon; collection between ECs was obvious; EC planted on UMBP, UCDFBP and LCDFBP could secrete endotheline(ET), the concentration of ET in supernatant fluid of LCDFBP was the highest. Conclusions above suggested that laminin was a significant contributing factor of LCDFBP for the improvement of cell-compatibility.Peripheral nerve regeneration through conduits made of GABP was tried. Two months after implantation, sciatic nerve and evoked muscle action potentials were founded. This experiment suggested that BP may be a promising guiding tissue regeneration materials.Studies in this paper were significant to BP which might be used as degradable biomaterial in tissue engineering.更多还原