Figure 6.

CSE generated an imbalance in the antioxidative system. Enzyme activities SOD (a), catalase (b), GPx (c), and GR (d) were determined with and without exposure to 5% CSE, 50 ng/ml or 320 ng/ml nicotine, and 100 ng/ml or 300 ng/ml cotinine. The enzymatic activity was expressed as the fold of control. Each experiment was conducted at least three times independently with triplicate. The statistical significance was determined by the Kruskal-Wallis H test followed by Dunn's posttest. Data are represented as the mean ± SEM, and the significance was represented as ^∗ p < 0.05, ^∗∗ p < 0.01, and ^∗∗∗ p < 0.001 vs the control group.