Oxidative stress was induced in carcinogenic metals alone treated mice. (A) Carcinogenic metals alone increased the expression level of NOX1, and decreased the expression level of antioxidant enzymes, such as SOD and catalase, in colon tissue. Exposure to As(III), Cr(VI), or their combination in drinking water for 20 weeks. The expression of NOX1, SOD1, SOD2, and catalase were determined by immunoblotting. The experiment was replicated three times. (B) The relative amounts of NOX1, SOD1, SOD2, and catalase were measured microdensitometrically and normalized to the expression of actin. Each data point was the mean ± SEM of three independent experiments. *p < 0.05, statistically significant difference from control group. (C) Immunofluorescence staining for 8-OHdG in indicated treatments. Green: 8-OHdG; Blue: DAPI. Magnification was 200×.