Effect of a 1-min pretreatment of 100% confluent HGFs with PA (1 mg/mL) on the cell viability (a) of, the amount of intracellular ROS per well (b) in, and the compensated amount of intracellular ROS per viable cell (c) in HGFs cultured in serum-free medium for 24 h.

<p>Since DCF was used as a standard, intracellular ROS level is expressed as DCF equivalent (nM). Each value represents the mean ± standard deviation (n = 4). Significant differences (p<0.05, Tukey–Kramer multiple comparison test) within each group are denoted by different letters (<i>i.e.</i>, bars with the same letter are not significantly different).