3D微结构打印掺锂β-TCP复合microRNA-21转染骨髓间充质干细胞治疗股骨头坏死的实验研究

Until recently, the pathogenesis of osteonecrosis of the femoral head(ONFH) has been unknown. Recent insight into ANFH has not identified satisfactory methods to increase blood circulation and promote bone regeneration in necrotic areas of the femoral head. Although a variety of methods have been developed, no ideal treatment protocol has been accepted as yet. Our previous data indicates microRNA-21 promotes expression of HIF-1α and VEGF-A by suppressing PTEN, which play significant roles in survival and angiogenesis of bone marrow mesenchymal stem cells. In addition, we find lithium induce osteogenic differentiation and proliferation of bone marrow mesenchymal stem cells by activating Wnt/β-catenin signal. Base on these results, we take advantage of the combination of microRNA-21 over-expression bone marrow mesenchymal stem cells and 3D printing of lithium-containing β-TCP. After core decompression of femoral head, the bone marrow mesenchymal stem cells (BMSCs) transfected with microRNA-21 will be transplanted to the bone defect areas in the femoral head. The examination of BMSCs proliferation, target gene expression and animal model will be performed to evaluate the effects of angiogenesis and bone regeneration. This study will provide a new therapeutic option for the treatment of oNFH with early and middle stage.

股骨头坏死至今发病机制不明，缺血坏死区的血运重建和骨组织修复非常困难，我们的前期研究发现microRNA-21通过抑制PTEN的表达进一步激活HIF-1α及其下游VEGF-A的表达，从而促进血管形成及细胞的生存能力。此外，我们的体外研究发现，通过运用锂剂可以通过激活骨髓间充质干细胞增殖及分化的重要调控通路Wnt/β-catenin，从而促进骨髓间充质干细胞增殖及成骨分化。本项目是既往工作的深入，拟通过3D微结构打印技术构建表面带有沟槽的掺锂β-TCP支架，从而提高其骨诱导性，其次将我们之前得到的转染microRNA-21的骨髓间充质干细胞整合到支架上促进其成血管能力，并检测此支架的生物学和力学性能，最后通过动物实验探讨这一复合生物支架是否可通过促进成血管成骨偶联对股骨头坏死具有修复作用，为股骨头坏死的早、中期治疗提供新的思路和方法。

激素性股骨头坏死为进展性的难治性疾病，给患者带来极大的痛苦，已成为非创伤性股骨头坏死的主要原因，其发病机制尚未完全阐明，目前尚无一种理想的治疗方法。我们的前期研究发现microRNA-21通过抑制PTEN的表达进一步激活HIF-1α及其下游VEGF-A的表达，从而促进血管形成及细胞的生存能力。此外，我们的体外研究发现，通过运用锂剂可以通过激活骨髓间充质干细胞增殖及分化的重要调控通路Wnt/β-catenin，从而促进骨髓间充质干细胞增殖及成骨分化。本研究发现转染microRNA-21对BMMSCs增殖分化影响的分子机制，可以修复骨坏死中骨髓间充质干细胞的损伤，促进其再生能力及治疗潜能。同时研究发现氯化锂可以通过激活β-catenin通路，促进成血管及平衡成骨/成脂分化，对大鼠激素性股骨头坏死发挥预防及保护作用。3D打印技术构建表面拓扑结构修饰的掺锂β-TCP支架可增强大鼠颅骨缺损修复，而将其复合转染microRNA-21的骨髓间充质干细胞可通过促进成血管成骨偶联对股骨头坏死具有修复作用。本研究的顺利完成为临床预防、治疗股骨头坏死及其机制的阐明提供一种新方法。