珍珠作为骨修复材料的应用基础研究

发布时间：2018-05-21 07:34

本文选题：骨修复 + 文石　；参考：《清华大学》2014年博士论文

【摘要】：珍珠层凭借优异的生物相容性和自身携带蛋白质的特点，近年来成为骨组织工程的一个研究热点。为了制备理想的骨组织工程支架，本论文探讨了文石和球文石珍珠水可溶基质的成骨特性，制备并表征了PLLA/文石和PLLA/球文石珍珠支架，通过动物实验证实了PLLA/文石和PLLA/球文石支架具有良好的促进骨再生的能力。将珍珠水可溶有机基质按分子量分为有机基质1kDa和有机基质3.5kDa，对比了文石和球文石不同分子量的有机基质对小鼠MC3T3-E1细胞和人骨髓间充质干细胞的作用。水可溶有机基质对两种细胞的增殖无促进作用，但能够促进两种细胞向成骨方向分化。细胞增殖和分化与有机基质的分子量无明显关系。水可溶有机基质能够促进小鼠MC3T3-E1细胞的矿化，缩短矿化时间。总的有机基质以及分子量1kDa的有机基质能够缩短人骨髓间充质干细胞的矿化时间。以上结果均适用于文石和球文石有机基质。采用冷冻干燥法制备了PLLA、PLLA/文石珍珠粉和PLLA/球文石珍珠粉支架。复合支架和PLLA支架具有良好的多孔结构，添加珍珠粉可以提高支架的压缩强度和压缩模量，而孔隙率略微下降。PLLA/文石珍珠粉、PLLA/贝壳珍珠层粉和PLLA/球文石珍珠粉复合膜的亲水性顺序为PLLA/文石PLLA/贝壳珍珠层PLLA/球文石，与复合膜吸附蛋白的实验结果吻合。细胞相容性实验表明，PLLA/文石和PLLA/贝壳珍珠层支架均能促进小鼠骨髓间充质干细胞的增殖和分化，而PLLA/球文石支架却有一定的抑制作用。体外降解实验表明，，PLLA/文石和PLLA/球文石支架降解行为类似，在PBS中降解呈略碱性，因此减缓了支架的降解速度。其原因在于碱性环境可以中和PLLA降解产生的酸性，影响孔隙率的变化，减缓PLLA分子量的降低等。在降解过程中，随着珍珠粉的不断溶解，复合支架的体密度不断下降，力学性能不断下降，但其力学性能一直高于PLLA支架。通过骨缺损修复的动物实验证实，PLLA/文石支架在8周时有加速成骨的作用，12周时新生骨已经与正常骨无异。PLLA/球文石支架在12周时也有很好的修复效果。说明PLLA/文石和PLLA/球文石支架均有良好的成骨作用。以上结果为珍珠作为骨修复材料的临床应用提供了理论和实验基础。
[Abstract]:The pearl layer has become a research hotspot in bone tissue engineering in recent years because of its excellent biocompatibility and the characteristics of its own proteins. In order to prepare ideal scaffolds for bone tissue engineering, the osteogenic properties of dolomite and ductile pearl hydrosoluble matrix were investigated in this paper, and PLLA/ ductile pearl scaffolds were prepared and characterized. Animal experiments have proved that PLLA/ and PLLA/ ball stone scaffolds have a good ability to promote bone regeneration. Pearl soluble organic matrix was divided into organic matrix (1kDa) and organic matrix (3.5kDa) according to molecular weight. The effects of different molecular weight organic matrix on mouse MC3T3-E1 cells and human bone marrow mesenchymal stem cells were compared. The water-soluble organic matrix did not promote the proliferation of the two kinds of cells, but could promote the differentiation of the two kinds of cells towards osteogenesis. Cell proliferation and differentiation were not related to the molecular weight of organic matrix. Water soluble organic matrix can promote the mineralization of mouse MC3T3-E1 cells and shorten the mineralization time. The total organic matrix and the organic matrix with molecular weight 1kDa can shorten the mineralization time of human bone marrow mesenchymal stem cells. The above results are applicable to the organic matrix of aragonite and globulitic stone. PLLA-PLLA / dolomite pearl powder and PLLA/ ball pearlite powder scaffold were prepared by freeze-drying method. The composite scaffold and PLLA bracket have good porous structure, adding pearl powder can improve the compression strength and modulus of the scaffold. However, the hydrophilic order of PLLA / dollite / pearl powder and PLLA/ ball pearl powder composite membrane is PLLA/ aragonite PLLA/ shell pearl layer PLLA/ nodular dolomite, which is consistent with the experimental results of the composite membrane adsorption protein. The cytocompatibility test showed that both PLLA / aragonite and PLLA/ shell pearl layer scaffolds could promote the proliferation and differentiation of mouse bone marrow mesenchymal stem cells, while PLLA/ spheroid stone scaffolds could inhibit the proliferation and differentiation of mouse bone marrow mesenchymal stem cells. In vitro degradation experiments showed that the degradation behavior of PLLA / aragonite and PLLA/ ductile stone scaffolds was similar and slightly alkaline in PBS, so the degradation rate of stents was slowed down. The reason is that alkaline environment can neutralize the acidity produced by PLLA degradation, affect the change of porosity and slow down the decrease of PLLA molecular weight. In the process of degradation, with the continuous dissolution of pearl powder, the bulk density and mechanical properties of composite scaffolds decreased, but the mechanical properties of composite scaffolds were always higher than those of PLLA scaffolds. The animal experiment of bone defect repair confirmed that PLLA / aragonite scaffold could accelerate osteogenesis at 8 weeks. At 12 weeks, the new bone had the same effect as normal bone. PLLA / bulbstone scaffold also had good effect at 12 weeks. The results showed that both PLLA/ and PLLA/ spheroidal stone scaffolds had good osteogenic effect. These results provide a theoretical and experimental basis for the clinical application of pearl as bone repair material.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R318.08

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