Fig. 1.
Intermittent hypoxia (IH) was toxic for HL-02 cells and inhibited their proliferation. HL-02 cells were exposed to IH (cycle of 5 min 2 % O2 and 10 min 21 % O2) or normoxia (21 % O2) for 4 days. a Effect of the IH on HL-02 cell viability. A total of 104 cells were seeded in each pool of 96-well plates, and then cell viability was assayed using CCK-8 after treatment. b Representative flow cytometry profiles of cell apoptosis probed by annexin V binding (horizontal) and PI exclusion (vertical). c Percentages of apoptotic HL-02 cells after IH treatment. *p < 0.05 vs the cells grown under normoxic conditions