Fig. 4.

Cell cycle of hUCB-MSCs at passage 3 cultured in hypoxia or normoxia were examined by flow cytometry. a Cell cycles of hUCB-MSCs cultured in low oxygen tension. b Cell cycles of hUCB-MSCs cultured in normoxia. c The percentage of cells in different phases of the cell cycle is presented in the histogram. Cells in hypoxia were compared with those in normoxia, the proportion of cells at the G₀/G₁ phase was lower (51.14 ± 5.1 % vs 65.67 ± 3.1 %), but the proportion of cells at S (46.9 ± 3.8 % vs 31.5 ± 2.9 %) and S + G₂/M (48.86 ± 5.2 % vs 34.33 ± 3.1 %) phases was higher (n = 3 per group, *p < 0.05)