外周血内皮祖细胞可增强骨髓间充质干细胞SDF-1和MCP-1的分泌并促进其归巢

Peripheral blood endothelial progenitor cells enhance the expressions of SDF-1 and MCP-1 of bone marrow stromal cells and promote their homing ability

目的本研究旨在探讨兔外周血内皮祖细胞(PB-EPC)对骨髓间充质干细胞(BMSC)体内归巢的影响及其作用机制。方法应用增强型绿色荧光蛋白(EGFP)慢病毒表达载体感染BMSC,构建生物骨移植修复兔桡骨缺损模型,实验组采用BMSC和PB-EPC(1∶1)联合培养细胞生物骨;对照组采用BMSC生物骨;空白组仅制作骨缺损不进行任何修复处理。三组均在2、4、8周,实时定量PCR检测骨缺损组织基质细胞衍生因子1(SDF-1)和单核细胞趋化蛋白1(MCP-1)mRNA的表达,ELISA检测血清SDF-1、MCP-1的蛋白水平;免疫组织化学染色检测骨缺损部位2、4、8周EGFP染色阳性率。结果在2、4、8周,实验组SDF-1、MCP-1的表达高于对照组和空白组;4周后实验组骨缺损部位EGFP表达阳性率高于对照组和空白组。结论PB-EPC可促进骨缺损部位BMSC SDF-1、MCP-1的表达且骨缺损部位EGFP表达阳性率增高。

Objective To investigate the effects of peripheral blood endothelial progenitor cells（ PB-EPCs） on the homing ability of bone marrow stromal cells（ BMSCs） as well as the potential mechanism. Methods BMSCs were injected intravenously with lentiviral expression vector expressing enhanced green fluorescent protein（ EGFP） for tracing. Biological bone graft was made to repair rabbit radial defect. In the experimental group,PB-EPCs and BMSCs mixed at a ratio of 1∶1were combined with partially deproteinized bone（ PDPB） for implantation to repair rabbit models with radial bone defect.BMSCs alone were combined with PDPB in the control group. The models in the blank group were not repaired. Protein and mRNA levels of endogenous stromal-derived factor-1（ SDF-1） and monocyte chemotactic protein-1（ MCP-1） were evaluated by ELISA and real-time quantitative PCR at 2,4,8 weeks after the operation. At the same time points,immunohistochemical staining was performed to detect EGFP expression in the defect sites. Results The mRNA and protein levels of SDF-1 and MCP-1 in the experimental group were higher than those in the other two groups. Immunohistochemistry showed that the number of EGFP-positive cells was larger in the experimental group than in the control or the blank group. Conclusion PB-EPCs can increase the expressions of SDF-1 and MCP-1 and promote the migration of EGFP-positive BMSCs to bone defect site.