Figure 4.

(a) Intracellular ROS was detected in Eca-190 cells after exposure to complex 2 (0, 20, and 40 μM) for 24 h under a fluorescence microscope. Representative photomicrographs from three independent experiments. Scale bars: 20 µm. (b) Apoptosis of Eca-109 cells was detected by flow cytometry after treated with different concentrations (0, 20, and 40 μM) of complex 2 for 24 h with or without NAC pretreatment. (c) Quantitative data analysis for the number of cells (% of total) in apoptosis for different treatment groups. Data were presented as mean ± SD (n = 3), Student's t-test, ^∗P < 0.05, ^∗∗P < 0.01.