Fig. 6. Long-term radon exposure enhances the number and function of mitochondria, and decreases oxidative stress in the cells. (A) Radon exposure decreased the ROS levels in the cells. (B) Radon exposure induced the protein levels of cytochrome C (upper panel). Relative ratio of Cytochrome C expression normalized to GAPDH is shown (lower panel). (C) Radon exposure time-course dependently increased the levels of ATP. (D) Radon exposure raised the copy number of mtDNA. (E) Radon exposure increased the levels of MMP. Results are expressed as means ± SD (n = 4). (*p < 0.05 indicated radon exposure times vs. control group).