FIGURE 1.

Effect of arsenite on UVR-induced oxidative DNA damage. A, HaCaT cells were incubated with the indicated concentrations of arsenite in serum-free medium for 24 h and then exposed to 8 J/cm² UV radiation on ice. 8-OHdG was measured by HPLC-EC 120 min after UVR exposure. The experiment was repeated at least three times. Bars represent the mean ±S.D.; ^*, p < 0.05 compared with UVR alone. B, HaCaT cells were incubated with 2 μm arsenite in serum-free medium for 24 h and then exposed to 8 J/cm² UV radiation on ice. 8-OHdG was detected by immunoperoxidase staining (upper panel) 120 min after UV exposure and quantified using image analysis software (lower panel). The arrows illustrate examples of 8-OHdG-positive staining. C, HaCaT cells were incubated with 2 μm arsenite (As) in serum-free medium for 24 h and then exposed to 8 J/cm² UV radiation on ice. After UVR exposure, cells were rinsed and incubated in serum-free medium for the indicated times with “0” representing cell collection on ice immediately after UVR exposure. Each experiment was repeated at least three times. Bars represent the mean ±S.D.; ^*, p < 0.05 compared with UVR alone.