Figure 3: Ox-LDL induces elevation of ROS levels through increasing NADPH oxidase activity. Human EPCs isolated from peripheral blood were treated with ox-LDL. (a) Represent images of cells after culture of EPCs with ox-LDL for 1 day. Images are visualized at ×200 magnification. Oxidative stress is indicated by green fluorescent dye. ((b), (c)) Intracellular ROS generation and NADPH oxidase activity are expressed as fold over normal control. versus control.