Figure 3.

Effects of macrolides on total HDAC activity and Akt phosphorylation under oxidative stress. (A) Reduction of HDAC activity in PMA-differentiated U937 cells, and reversal by N-acetyl cysteine (NAC). Cells were treated with PMA (50 ng mL⁻¹) for 48 h, and NAC 100 μM was treated 20 min before and 24 h after PMA treatment. (B) Effects of macrolides on total HDAC activity in PMA-differentiated U937 cells. Cells were pretreated with macrolides (10 to 330 μM) for 20 min and then treated with H₂O₂ (1 mM) for 30 min. Total HDAC activity was determined by in-cell HDAC activity assay. (C) Effects of macrolides on H₂O₂-induced phosphorylation of Akt in PMA-differentiated U937 cells. Cells were pretreated with macrolides (33 to 330 μM) for 20 min, followed by H₂O₂ (1 mM) stimulation for 30 min. Phosphorylation levels of Akt were measured by Western blot (C) and calculated relative to total Akt protein (D). Values represent means of three experiments ± SEM. ^#P < 0.05 (vs. vehicle control), *P < 0.05, **P < 0.01 (vs. treatment with H₂O₂).