Reactive oxygen species (ROS) assay

ROS intensity in the control and UVR-treated retinal cells was measured by the carboxy-H2DCF-DA dye (Invitrogen, Shanghai, China) assay [45]. Following the treatment, cells were incubated with 1 μM of carboxy-H2-DCFDA for 120 min under the dark, which were then washed with warm PBS and immediately tested by a spectrofluorometer at excitation and emission wavelengths of 485 and 535 nm, respectively. The results were expressed as increase in fluorescence with respect to control cells.