FIGURE 3.

Effects of CTS on mitochondrial function in UV-irradiated HaCaT cells and HFF-1 cells. HaCaT cells and HFF-1 cells were treated with CTS (0, 0.02, 0.05, 0.1 μM) for 4 h and then irradiated with UVB (200 mJ/cm²) and UVA (15 J/cm²), respectively. After UV irradiation, the cells were supplemented with the corresponding concentrations of CTS and incubated for the different times before analysis. (A) Fluorescence staining of Mito-Tracker Green probed HaCaT cells after 1-h of incubation following UVB irradiation. Scale bars: 50 μm. The plot shows the quantitation of mitochondrial mass as determined by intensity analysis of the fluorescence in HaCaT cells. (B) Fluorescence staining of Mito-Tracker Green probed HFF-1 cells after UVA irradiation. Scale bars: 50 μm. The plot shows the quantitation of mitochondrial mass as determined by the intensity analysis of the fluorescence in HFF-1 cells. (C) Copy number of mtDNA in HaCaT cells as determined by qPCR. (D) Copy number of mtDNA in HHF-1 cells as determined by qPCR. (E) JC-1 staining of HaCaT cells after 1-h of incubation following UVB irradiation. Scale bars: 50 μm. The ratio of red to green fluorescence intensity represents MMP. The plot shows the change in MMP level in HaCaT cells. (F) JC-1 staining of HFF-1 cells after UVA irradiation. Scale bars: 50 μm. The ratio of red to green fluorescence intensity represents MMP. The plot shows the change in MMP level in HFF-1 cells. (G) ATP level in HaCaT cells following UVB irradiation as detected by Multi-Mode Microplate Reader. (H) ATP level in HFF-1 cells following UVA irradiation as detected by Multi-Mode Microplate Reader. All data are mean ± SD from three independent experiments, “##” indicates significantly different from the control (no irradiation and CTS treatment) at the p < 0.01 level, whereas “*” and “**” indicate significantly different from the UV-irradiated cells without CTS pretreatment at the p < 0.05 and p < 0.01 levels, respectively.