矿物化淫羊藿苷-小肠黏膜下层复合组织工程骨的构建和机制研究

Small intestinal submucosa(SIS) is a natural extra cellular matrix (ECM) material. 90% of SIS is collagen I which is very similar to organic component of bone and SIS also contains angiogenic cytokines like VEGF which is good for bone regeneration.SIS patch would be studied as a bone tissue engineering scaffold to load drug and to support cell growth, differentiation. The combination of icariin, calcium enriched medium and BMP-2 will be applied to induce osteogenic differentiation in MC3T3-E1, NIH3T3 and C3H10T1/2 cell lines. The mechanism of synergistic effect of 3 osteogenic compounds will be studied and the method which is able to differentiate osteoblasts, fibroblasts and mesenchymal stem cells with programmed combination of osteogenic compounds would be fully optimized. SIS patch is prepared with icariin to develop a sustained drug release system. With seeded cells on the icariin-SIS patch, optimized combination of osteogenic compounds (calcium enriched medium, BMP-2 and icariin) is applied to induce osteogenic differention together with significant natural mineralization on SIS patch. The in vitro engineered bone like tissue would be evaluated with various assays in vitro and also in vivo critical size bone defect model.

猪小肠黏膜下层（SIS）作为一种天然的细胞外基质材料，具有和骨类似的有机成分，并且含有如VEGF等的促血管再生因子，非常适合用来作为骨组织工程的基质材料。本课题利用SIS补片作为骨组织工程骨架材料，通过补片载药和体外组合诱导，培育高度矿物化的小肠黏膜下层组织工程骨，并对其进行评估。研究将首先利用细胞模型研究淫羊藿苷、富钙培养基和BMP-2三种成骨促进因子促进成骨分化的不同特性，考察三种促骨生长因子对于成骨分化不同阶段的作用以及三者之间的协同促进成骨分化的关系，并确定最有效的诱导体外矿物化和成骨分化的药物组合模式。同时研究在SIS补片上载入淫羊藿苷，建立使淫羊藿苷能够从SIS上缓慢稳定释放的药物材料复合体系；并在此复合材料上，植入种子细胞，在体外通过组合成骨诱导因子培育形成高度矿物化并且具有类骨及促骨再生特点的组织工程骨，并对此工程骨的生物学活性和生物力学特性进行评估。

细胞外基质由于具有优异的生物相容性、仿生性和生物学活性,被认为是理想的组织工程材料。由于在体外很难模拟复杂的细胞外基质，目前多用胶原和羟基磷灰石等骨基质主要组分，通过物理、化学方法来修饰改造构建复合骨架材料，但这些复合材料存在仿生性一般、生物学活性单一等不足。SIS具有和原始骨类似的有机成分，并且保留了很多促进血管形成的活性因子，但机械强度和成骨诱导性不足。本项目利用细胞组装ECM技术构建的矿物化SIS工程骨比简单复合材料有更接近原始骨的组成、机械强度和生物学活性，同时还能够加速体内骨骼再生和修复。本工程骨无论外观（微观结构）、生物相容性还是生物学活性都非常优异，可以说具有人造骨4大核心因素。此外SIS来源丰富、价格低廉，并且已被FDA批准可用于体内植入，因此基于SIS的复合工程骨具有良好的市场前景。