Figure 1. Cell viability and heme oxygenase-1 (HO-1) expression in human retinal pigment epithelial cells (ARPE-19) with different concentrations of curcumin-containing medium. ARPE-19 cells were exposed to various concentrations of curcumin for 3 h. Cell viability (A) was measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and HO-1 protein expression (B) was measured with western blot analysis. The non-treated and curcumin-treated groups showed no significant difference in cell viability, and HO-1 expression was highest in 15 μM curcumin.