Cell proliferation test were divided into three types as shown in Table 2. The cells were seeded onto the specimens at a density of 1.8 × 105 cells/80 μl. After the cells’ attaching to the specimens, the compressive stimulation was applied to the cells by using the prepared apparatus. At each time of 1-, 3- and 5-day culture, the specimens were moved to new 12-well plates and added with fresh culture medium. Ten percent (v/v) CCK-8 reagent was added to immerse well and incubated at 37 °C in a humidified 5 % CO2 for 4 h. One-hundred microlitre of the reactant were moved into a 96-well plate and the absorbance read was obtained on a micro-plate reader at 450 nm. The cell number was calculated by initial absorbance value.Table 2Conditions of cell proliferation experiment in accordance with the stimulationScaffold typesCompressive stimulationConditionsControl groupX37 °C/5 % CO2 Control groupO37 °C/5 % CO2 Experimental groupO37 °C/5 % CO2