Figure 5. Effect of blue light on expression of stress-related proteins. The figure shows flow cytometric analysis of HO-1 (A), SOD-Mn (B), osteopontin (C), Cathepsin D (D), Hsp-27 (E), and CML (F) expression in ARPE-19 cells. Cells were irradiated at 1 mW/cm² (blue) and 0.3 mW/cm² (green) or unirradiated (black) for 24 h (C, F), 48 h (Hsp-27), or 72 h (A, B, D). Fluorescence intensity distribution correspond to expression of appropriate protein or CML expression. Blue light with an output power of 1 mW/cm² enhanced expression of stress-related proteins.The expression of cathepsin D increased in cells also after a lower blue light output power of 0.3 mW/cm². Results are representative of 3 separate experiments.