Fig. 3.

Growth kinetics of hUCB-MSCs of passage 3. a A standard curve relating cell density and optical density values. The number of cells was calculated using the formula: number of cells = 0.00006 × OD value + 0.1509. b The proliferation ability of hUCB-MSCs cultured in normoxia or hypoxia. The population doubling time of hUCB-MSCs cultured in normoxia was 65.72 ± 1.7 h, while that of hUCB-MSCs cultured in hypoxia was 49.87 ± 2.0 h (n = 3 per group, *P < 0.05). c Cell growth rates of hUCB-MSCs cultured in hypoxia or normoxia were statistically different after 3 days (n = 3 per group, *P < 0.05). d Cells cultured under normoxia or hypoxia were stained with β-galactosidase (β-gal). Normoxic cells increased in the percentage of β-gal expression compared with hypoxic cells (n = 3 per group, *P < 0.05)