Abstract: OBJECTIVE: To investigate the induction of oxidative stress by arsenious acid solution As(Ⅲ) in human lung cancer A549 cells. METHODS: Cultured A549 cells were exposed to arsenious acid solution, As(Ⅲ), at doses of 0, 2.5, 5, 10 and 200 μg/mL for 24 h. Cell viabilities were determined using the CCK-8 assay. For cells exposed to 0, 2.5, 5 μg/mL doses for 24 h, superoxide dismutase (superoxide dismutase, SOD) in cell culture medium was detected using ELISA, and intracellular reactive oxygen species (ROS) were detected using fluorescent probe DCFHDA. RESULTS: As exposure concentration of As(Ⅲ) increased, A549 cell viabilities were gradually decreased (r=0.99, P < 0.05). The level of SOD in the 2.5, and 5 μg/mL exposure groups were (0.72±0.05), and (1.10±0.16) ng/mL, respectively, which were higher than that of the control group[(0.56 ±0.03) ng/mL] (P < 0.05). Relative fluorescence intensities of ROS were (169.31 ±6.13)%, and (242.60±2.35)% for the same two groups which were higher than that of the control group (100±2.80)%. CONCLUSION: As(Ⅲ) exposure caused significantly reduced cell survival rates, increased concentrations of SOD and ROS in A549 cells. Oxidative stress may therefore be an important mechanism for the toxicity of As(Ⅲ).

Key words: arsenious acid solution, oxidative stress, human lung cancer A549 cells, superoxide dismutase, reactive oxygen species