Fig. 4

Hypoxia induced HepG2 cell proliferation through EPO/EPOR. a MTT assay. HepG2 cells were cultured under normal oxygen or hypoxia for 24, 48 and 72 h. *p < 0.05 hypoxia vs normoxia at the same time point, **p < 0.01 hypoxia vs normoxia at the same time point, ^## p < 0.01 hypoxia with soluble-EPOR vs hypoxia. b Histogram plots of CFSE fluorescence of cells cultured under normoxia or hypoxia with or without soluble-EPOR. The value (inset) for the percentage of cells that divided at least once (top left) and the average number of cell divisions (bottom left corner) are indicated for each sample. c Histograms of percentage of divided cells. N24, N48 and N72 indicated cells cultured for 24, 48 and 72 h, respectively. H24, H48 and H72 indicated cells cultured under hypoxia for 24, 48 and 72 h, respectively. Data shown are mean ± SEM of at least three independent experiments, each with three replicate wells. Student’s t test is indicated. *p < 0.05 hypoxia vs normoxia at the same time point, **p < 0.01 hypoxia vs normoxia at the same time point, ^# p < 0.05 hypoxia with soluble-EPOR vs hypoxia, ^## p < 0.01 hypoxia with soluble-EPOR vs hypoxia. Student’s t test is indicated