Figure 4: Melatonin inhibits H2O2-induced apoptosis-related protein expression in RPE cells. ARPE-19 cells were pretreated with the different concentrations of melatonin (50 and 100 μM) for 48 h and exposed to 300 μM H2O2 for 24 h. Expression levels of apoptosis-related proteins (caspase 7, cleavage-caspase 7, Bcl-2, Bax, and Cyt c) are displayed in (a–f). Protein expression was calculated from densitometry absorbance values of three separate experiments after they were corrected for GAPDH/β-actin expression to obtain equal loading. Values are the mean ± SD. versus the control group and versus H2O2-treated cells.