Objective      To establish a co-culture system containing mouse endothelial progenitor cells (EPCs) and mouse osteoclast precursor RAW264.7.       Methods      Co-cultured endothelial progenitor cells (EPCs) and RAW264.7 cells in Transwell chamber served as the experimental group

and the equivalent cells nutrient solution but without EPCs cells served as control group. Cell Counting Kit-8 was used to measure cell proliferation. Absorption values were detected to depicter cellular growth curve. Reverse transcript PCR was applied to detect VEGFR-2 and CXCR4 expression at mRNA level. TRAP staining was used to detect osteoclast activity.       Results      Co-culture  system of mouse endothelial progenitor cells (EPCs) and RAW264.7 cells in Transwell chamber facilitated RAW264.7 cells growth. In comparison with the growth of RAW264.7 cells in control group

the cell growth in co-culturing system was significantly increased after culture for 3

5 and 7 d (P0.01). Co-culture also increased the expression of vWF and VEGFR-2 and the activity of osteoclast.       Conclusion      In our co-culture system of EPCs and RAW264.7 cells

EPCs facilitate the proliferation and differentiation of RAW264.7 cells.