Abstract: 【Abstract】Objective the purpose of this study is to investigate the behavior of calcuim and phosphate ions releasing from calcium phosphate cement after immediatly immersed and the affect of cell proliferation of RAW264.7 by CPC extraction. Methods CPC specimens were immersed in DMEM for 1h, 2h, 3h, 6h, 12h, 1d, 2d, 3d. The medium was refreshed at each timepoint. The concentration of calcium and phosphate ions releasing from CPC were detected by resultsinductively coupled plasma optical emission spectrometry，ICP-OES. RAW264.7 were cultured in DMEM medium(group B) and DMEM medium+CPC specimens(group CPC) respectively, the proliferation capacity of RAW264.7 were affected by CPC tested with MTT method. Results In DMEM immersing groups, all the concentrations of calcium in medium-refreshed group were higher than these in medium-without-refreshed group(P＜0.05) after refreshed the medium. The concentration of phosphate got a peak value 4.380±0.019mmol/L at 1h in medium-refreshed group. After that, the precipitation amount decreased obviously, and the 2h phosphate concentration was 1.944±0.109 mmol/L (P＜0.05). The calcium increased slowly at the beginning, reaching the peak concentration of 1.590±0.064mmol/L at 6h, then decreased gradually.The cell proliferation of group CPC reached its nadir which was 67.23% at 1d, but the peak point was 95.93% at 7d. Conclusion The group CPC immersed in DMEM can provide a theoretical base for experiments of CPC extraction in vitro. Proliferation of RAW264.7 wasn't affected evidently by CPC.

Key words: 【Key words】 Calcium phosphate cement, Calcium, phosphate, Monocyte-Macrophage Precursor Cells, Proliferation