SDF-1趋化诱导骨组织再生机制的实验研究

Stromal cell derived factor -1 (SDF-1) can induce the bone marrow mesenchymal stem cells (BMSCs) to the damaged tissue and promote the repair. We have confirmed that SDF-1 and its specific receptor CXCR4 did not express in the surrounding tissue of normal bone; the expression of SDF-1 and its specific receptor CXCR4 was increased when fracture happened. Therefore, we proposed a hypothesis: BMSCs can be induced by SDF-1/CXCR4 to the fracture site in the early stage of bone healing to promoting bone tissue regeneration and repair. To test this hypothesis, we will investigate the role of SDF-1/CXCR4 in the repair of bone injury from molecular, cell and animal level to make clear its mechanism.We will take measures such as immunohistochemistry, real - time PCR, Western blot, in vitro and in vivo migration assays. The study explain the mechanism of the repair of damaged bone by chemotactic，and to accelerate bone regeneration process through enhancing BMSCs chemotactic effects，which provide new ideas for the treatment of large segmental bone defect.

基质细胞衍生因子-1（SDF-1）可以趋化诱导骨髓间充质干细胞（BMSCs）到达损伤组织促进其修复；我们已证实：在正常骨组织周围，并没有SDF-1及其特异性受体CXCR4表达；当骨组织损伤后，SDF-1及其特异性受体CXCR4表达增多。为此，我们提出假说：在骨愈合早期阶段，BMSCs可通过SDF-1/CXCR4被趋化诱导至骨折部位，促进骨组织再生修复。为了验证这一假说，我们通过BMSCs系和动物模型，采用免疫组化、real –time PCR、western blot、体内外趋化实验等手段，分别从分子、细胞及动物试验等方面探讨SDF-1/CXCR4在骨损伤修复中的作用，以明确其机制。本研究通过趋化诱导促进骨组织再生这一新视点来阐述骨折修复的机制，并通过增强BMSCs的趋化诱导作用来加速骨组织再生过程，为治疗大段骨缺损提供新思路。

骨折愈合周期长、骨缺损愈合困难等临床难题亟待解决；BMSCs被证实可促进骨折愈合，但是促进骨髓间充质干细胞(BMSCs)趋化到骨折部位仍是尚未解决的关键问题；.我们研究证实: 基质细胞衍生因子-1(SDF-1)可以趋化诱导BMSCs到达损伤组织；在正常骨组织周围,并没有SDF-1及其特异性受体CXCR4表达；当骨组织损伤后,SDF-1及其特异性受体CXCR4表达增多；且损伤组织周围新生血管表达增多；并且在支架内部SDF-1的作用下，BMSCs可通过SDF-1/CXCR轴趋化诱导至支架内部，增强了支架的生物化在低氧的条件下，低氧诱导因子-1（HIF-1）表达增多，且低氧导致BMSCs表面受体表达CXCR4水平增高。因此,我们通过实验验证:在骨愈合早期阶段, SDF-1表达增多增强血管化，BMSCs可通过SDF-1/CXCR4被趋化诱导至骨折部位,促进骨组织再生修复，并可以通过骨组织工程的方法，构建低氧/SDF-1支架，加强支架生物化，完成骨缺损的修复。.实验中, 我们通过BMSCs系和动物模型,采用免疫组化、Real-time PCR、western blot、体内外趋化实验等手段,分别从分子、细胞及动物试验等方面探讨SDF-1/CXCR4在骨损伤修复中的作用, 以明确其机制。.本研究通过SDF-1/CXCR4增强血管化趋化诱导促进骨组织再生这一新视点来阐述骨折修复的机制,并通过增强BMSCs的趋化诱导作用来加速骨组织再生过程,为解决临床难题提供新方法。