Figure 4 Effect of lutein on the apoptosis of keratinocytes treated with UBV measured by annexin V-FITC assay. Apoptosis of keratinocyte cell line (A, B) and primary human keratinocytes (C, D) treated with 0.5 to 15 μM of silk lutein (A, C) or c-lutein (B, D) for 24 hours prior to irradiation with UVB at 24 mJ/cm2. Each bar represents the percentage of cells undergoing apoptosis. Error bars are one standard deviation. *, p < 0.05