Figure 4.

Induction of ROS accumulation in HeLa cells. Accumulation of ROS in HeLa cells by DCFH-DA staining (A) or DHE staining (C). HeLa cells were treated with 20 or 40 μM of ONP for 24 h, followed by incubation with the ROS probe DCFH-DA (10 μM) or superoxide probe DHE (10 μM) for 30 min. The bright-field (top panel) and the fluorescent-field (bottom panel) pictures from three independent experiments were imaged and acquired by an inverted fluorescence microscope. The fluorescence intensity in individual cells from (A) and (C) was quantified by ImageJ versus the control group and was shown in (B) and (D). **p < 0.01 versus the control groups. Scale bars: 20 μm.