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

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 1:1 were 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.