Figure 4

ELF-PEMF exposure increases protein levels and function of antioxidative enzymes in hOBs. hOBs were osteogenically differentiated with or without daily exposure to ELF-PEMF. After 2 days protein levels of SOD2, CAT, GPXs and GSR were determined by Western blot. (a–d) Signal intensities were quantified by densitometric analysis using the ImageJ software. Individual samples (N = 9) were analyzed twice (n = 2) to reduce small loading differences. The mean signal intensity of cells on day 0 was set as reference. *p < 0.05, **p < 0.01 and ***p < 0.001 as indicated (Kruskal-Wallis test followed by Dunn’s multiple comparison test, α = 0.05). (e) Changes in enzyme activities (N = 10; n ≥ 2) were determined using test kits. (f) ROS levels in hOBs (N = 12, n = 4) after single and repetitive exposures to ELF-PEMF (7 min per day) and additional H₂O₂ (0.01%) stimulation. ROS levels were determined using the DCFH-DA assay. Results are given as fold of H₂O₂ treated hOBs. *p < 0.05 and **p < 0.01 as compared to unexposed cells on day 2 (two-tailed Mann-Whitney test, α = 0.05).