Fig 1.
Blue light effect on the viability of B16F10 melanoma cells.
Cells were treated with blue light (0, 1, and 2 h / day) for 3 days. A. Cell viability measured by MTT assays each day. B. Cell survival rate measured by trypan blue assays each day. C. Cell were irradiated once, returned to the dark incubator, and cell numbers were counted by cell counter every following day. D. Cells were immediately stained with apopxin green (apoptosis) and CytoCalcein Violet 450 (live cell) after the last irradiation, and images were taken with a fluorescent microscope. Scale bar, 500 μm. E. Fluorescence values for green were analyzed by image J. NL: non-light treatment; BL: blue light irradiation; B1h, B2h: blue light irradiation 1, 2 hours. The results are presented as the mean ± SD; n ≥ 3; *p < 0.05, ***p < 0.001 vs. NL 0.
Fig 2.
Blue light effect on the migration of B16F10 melanoma cells.
Cells were irradiated with blue light for 0, 1, or 2 h after preparing the gaps using pipet tips. Yellow lines labeled the area without cells. The images at 0 h and 18 h were taken and the area change of cross gap was analyzed by image J. The bar graphs show the chage of the area between 0 h and 18 h. NL: non-light treatment, BL: blue light irradiation. The results are presented as the mean ± SD; n ≥ 3; **p < 0.01, ***p < 0.001 vs. NL 0.
Fig 3.
Blue light induced ROS generation and DNA damage in B16F10 melanoma cells.
After irradiation, the cells were immediately assayed using the DCF-DA (A, B) or DNA damage kit (C,D), the pictures were taken by fluorescent microscope. The fluorescent of DCF-DA was measured by microplate reader (B). The images of DNA damage were analyzed by Image J. A, B. Blue light induced ROS generation in B16F10 melanoma cells. C, D. Blue light induced DNA damage in B16F10 melanoma cells. The length of the scale bar in A and C is 100 μm and 500 μm, respectively. Clear field of the cell after blue light irradiation was shown at S3 & S4 Figs in S1 File. NL: non-light treatment, BL: blue light irradiation. The results in B and D are presented as the mean ± SD; n ≥ 3; **p < 0.01, ***p < 0.001 vs. NL 0.
Fig 4.
Blue light enhanced melanogenesis in B16F10 melanoma cells.
Cells were treated with blue light (0, 1, and 2 h / day) for 3 days, and the cells from day 3 were collected. A. The melanin content increased by blue light irradiation. B-D. mRNA quantity determined immediately after irradiation (0 h) by real-time PCR. E-H. mRNA quantity 3 h after irradiation by real-time PCR. NL: non-light treatment, BL: blue light irradiation, tyr: tyrosinase. The results are presented as the mean ± SD; n ≥ 3; *p < 0.05, **p < 0.01, ***p < 0.001 vs. NL 0.