Objective: To investigate the relationship between the hormesis of proliferation and oxidative stress induced by sodium arsenite (Na(2)AsO(2)) in human embryo lung fibroblasts (HELF).
Methods: HELF were treated with Na(2)AsO(2) of 0.0, 0.1, 0.5, 1.0, 5.0 and 10.0 micromol/L for 4 hours or 24 hours, respectively. The cell proliferation, the reactive oxygen species (ROS) level, the malondialdehyde (MDA) content and the activity of glutathione peroxide (GSH-Px) and the superoxide dismutase (SOD) in HELF were detected respectively.
Results: The HELF proliferation induced by 0.1 and 0.5 micromol/L Na(2)AsO(2) was significantly higher than that in the control group (P < 0.01). The HELF proliferation induced by 5.0 and 10.0 micromol/L Na(2)AsO(2) was significantly lower than that in the control group (P < 0.01) with the dose-effect relation of an inverted U curve. The ROS level induced by Na(2)AsO(2) of between 0.5 and 10.0 micromol/L was significantly increased (P < 0.05, P < 0.01). The positive correlation was found between the ROS level and the exposure dose of Na(2)AsO(2) (r = 0.934, P < 0.01). The 5.0 and 10.0 micromol/L Na(2)AsO(2) induced the significant increase of the MDA contents (P < 0.01) and the significant decrease of the GSH-Px activity compared to those in the control group (P < 0.01). The SOD activity in 0.5 micromol/L Na(2)AsO(2) group was significantly higher than that in the control group (P < 0.01) while the SOD activity induced by 5.0 and 10.0 micromol/L Na(2)AsO(2) was significantly decreased (P < 0.01) if compared with the control group with the dose-effect relation of an inverted U curve.
Conclusion: The sodium arsenite can induce the hormesis of proliferation in HELF with the dose-effect relation of an inverted U curve. The mechanisms probably relates to different levels of oxidative stress induced by sodium arsenite of different concentrations.