Objective   To explore the effect of compressive stress on the proliferation of the human bone marrow stromal cells (hBMSCs) seeded on demineralized bone matrix (DBM) and its optimal range of intensity.    Methods   The tissue engineered bone was built with the method of double phase inoculation after the hBMSCs were isolated and cultured from fresh bone marrow sample of healthy individual and DBM was cut into a cube of 10 mm. Compressive stress with the power to make the cell body shrink by a ratio of 2%

5%

10%

15% or 20% at 0.5 Hz

was applied to the hBMSCs for 2 h per day. The cells were harvested after the stimulus for 1

3

5

7

10 and 13 d respectively. Cell morphology was observed with inverted microscopy

and the ultrastructure of the tissue engineering bone with scanning electron microscopy. Proliferation and cell cycle was measured by MTT assay and flow cytometry respectively.    Results   Compressive stress promoted hBMSCs seeded on DBM to proliferate when the compression ratio was 2%

5% or 10%; but restrain the cells to proliferate when the compression ratios were 15% and 20%. Among all of the compression ratio

10% showed a most prominent effect on cell proliferation. It increased the percentage of cells at the S phase from (19.15±0.26)% (in control group) to (27.45±0.25)%.    Conclusion   Compressive stress promotes the hBMSCs to proliferate in a certain range of intensity

and the intensity with the power to shrink the cell body by 5% to 10% is an optimal range to apply.