Figure 2.

Effects of PAR on the metabolic activity of human OS cell lines (SaOS-2, MG-63, U2-OS) and healthy hBM-MSC with treatment time. Cells in adherent culture were exposed during 2 h to PAR treated by APPJ or kINPen for 1, 2.5 and 5 min. After that, PAR was replaced by fresh medium. Metabolic activity was determined 24 h (A) and 72 h (B) after PAR exposure by WST-1 test. (C) Cells were also exposed during 2 h to increasing concentrations of H₂O₂ and NO₂⁻ standards in Ringer’s saline with 10% FBS (which match with concentrations determined in Figure 1), corresponding to 50, 100 and 200 µM for H₂O₂ (Ci) and 10, 20 and 40 µM for NO₂⁻ (Cii) and metabolic activity was determined 24 h after exposure. Values were relativized to cells exposed to untreated PAR. Asterisks represent statistically significant differences among cell lines for the same PAR treatment time-point. (n = 3; *** p-value < 0.005, ANOVA and two-sided Student’s t-test).