Figure 4. YC-1 increased cell apoptosis under chemical hypoxia. A: After treatment with 0.066% DMSO or 200 µM CoCl₂ in the absence or presence of 20 µM YC-1 for 24 h, 661W cells were stained with annexin V (for apoptotic cells) and propidium iodide (for necrotic cells) and measured and analyzed by flow cytometry. B: The frequency of apoptosis was quantified from three independent experiments (n=3). * Indicates p<0.05 compared to DMSO vehicle group; ^# indicates p<0.05 compared to the chemically induced hypoxic group.