Figure 2. Light exposure induces DNA damage. A: The purified plasmid PBR322 was exposed to 2,600 lx light for 3 days and then examined with 1% agarose gel electrophoresis. LP, line plasmid. CP, circle plasmid. Lt, light situation. Dark, dark control. B: The isolated genomic DNA from RGC-5 cells was exposed to 2,600 lx light for 3 days and then examined with 1% agarose gel electrophoresis. Lt, light situation. Dark, dark control. C, D: The TUNEL assay was used to show the breakdown of DNA in dead cells. RGC-5 cells were exposed to 2,600 lx light for 2 days (C) or no light for 2 days (D). DNA strand breaks were positively detected with TUNEL and denoted with asterisks (*). Scale bars=15 μm.