SDF-1α基因转染BMSCs动员内皮祖细胞治疗兔激素性股骨头坏死

股骨头坏死致残率高，缺乏满意治疗方案，干细胞移植是一种很有前景的生物学疗法。细胞移植治疗股骨头坏死有两个关键点：提供可靠的成骨种子细胞；促进坏死区域的血管生成。BMSCs是目前移植效果较为肯定的种子细胞。我们在前期工作中证实，借助SDF-1α/CXCR4生物轴可快速动员并募集EPCs加速损伤血管内皮修复。在此基础上，本项目建立兔激素性股骨头坏死模型，将SDF-1α基因转染的BMSCs植入股骨头坏死区，修饰后的BMSCs可分化为成骨细胞，修复坏死区骨组织，并持续分泌SDF-1α，通过SDF-1α/CXCR4生物轴快速动员并自动俘获EPCs，促进坏死区再血管化，使成骨与血管生成同步进行。拟采用RT-PCR、Western blot等观察基因修饰对BMSCs增殖分化的影响，应用免疫荧光技术追踪移植细胞的分化及转归, 借助Micro-CT骨扫描、血流灌注技术评价坏死部位骨组织修复及血管再生情况。

Osteonecrosis of femoral head (ONFH) is characterized with progressive course and high disability. Various treatments can be used among which stem cell transplantation is considered as the most promising biological method. Generally, local transplantation of osteogenous seed cells and stimulative revascularization are believed to be the key points in stem cell transplantation for ONFH. Bone marrow mesenchymal stem cells (BMSCs) represent a highly reliable candidate for cell-based therapeutic approaches. Our previous studies demonstrated that endothelial progenitor cells (EPCs) could be rapidly mobilized from bone marrow and recruited to accelerate the repair of damaged vascular endothelium through the SDF-1α/CXCR4 biological axis. In this study, BMSCs are transfected with SDF-1α and transplanted for treating steroid-induced ONFH in rabbits. SDF-1α transgenic BMSCs can differentiate into osteoblast and at the same time express SDF-1α continually. Then, autologous EPCs are mobilized and recruited to initiate rapid neovascularization and therefore promote osteogenesis in the necrotic lesion through the SDF-1α/CXCR4 biological axis. RT-PCR and Western blot are used to detect the changes of proliferation and differentiation of BMSCs after SDF-1α gene transfection. In vivo differentiation and survival are confirmed using immunofluorescence and immunohistochemistry. Bone regeneration and revascularization of the necrotic area of the femoral head are evaluated with the assistance of X ray, MRI, and Micro-CT scanning.