Activation of ERK1/2 in FOH-treated neutrophils. Neutrophil cells (1 × 106 cells/well) were suspended in PBS in 12-well microplate and stimulated with FOH at concentrations of 100 µM and 200 µM. Unstimulated cells served as a negative control, and PMA-treated cells were a positive control. After 1 h, the cells were lysed, and the amount of total and phosphorylated ERK1/2 was quantified using ELISA Kit SimpleStep (Abcam). Data represent the mean values of absorbance ± S.E.M. from two replicates as the percentage ratio of phosphorylated ERK1/2 to total ERK1/2. ANOVA and Tukey post-tests were used. Asterisks denote statistical significance (p > 0.1234–ns, * p ≤ 0.0332, ** p ≤ 0.0021).