Figure 7. The ROS generation detection by DCFH-DA.

(a) Effect of active oxygen scavengers on cell damage after SDT. To find out which one was the main inducer in apoptosis after SDT, several free radical scavengers such as 200 U/mL catalase (CAT, scavenger of hydrogen peroxide), 100 μg/mL superoxide dismutase (SOD, scavenger of superoxide anion radical), 100 mM mannitol (scavenger of hydroxyl radical) and 10 mM Sodium azide (NaN₃, scavenger of singlet oxygen) were employed before treatment. The cell viability was checked by the CCK-8 assay. Ultrasonically induced cell damage were significantly reduced in the presence of NaN₃ but not in the presence of CAT, SOD or mannitol, indicating singlet oxygen may be the main factor for cell damage. (b) Fluorescent photomicrograph of THP-1 macrophages stained by DCFH-DA showing intracellular ROS. (c) Intracellular ROS generation in THP-1 macrophages. ***p<0.001 vs. control. #p< 0.05 vs. SDT. Scale bar  =  0.1 mm.