Photobiomodulation at Defined Wavelengths Regulates Mitochondrial Membrane Potential and Redox Balance in Skin Fibroblasts

Figure 2

Effect of the different wavelengths on the mitochondrial membrane potential of fibroblasts. (a) Exposure protocol: cells were exposed for 20 s, either once, twice, or three times. Multiple exposures were performed at 24 hr intervals. Twenty-four hours after the final exposure, cells were stained with the MitoTracker fluorescent dye and fixed. Cultures not exposed to light were processed for the same time, and used as control groups for each protocol. (b) The graph shows the relative MitoTracker intensity, measured for each wavelength exposure (440, 525, 645, 660, 780, and 900 nm) and each exposure protocol (EXP1, EXP2, and EXP3). Results are expressed as a percentage of the nonexposed group (100%; horizontal dotted line) for each time point; n = 9 (nonexposed), 6 (exposed). (c) Representative images of cells exposed to different LEDs (440, 525, 645, 660, 780, and 900 nm) using the different protocols: EXP1 (24 hr), EXP2 (48 hr), and EXP3 (72 hr). Nonexposed control groups (Ctrl) are included in the panel. Scale bar: 50 µm. Statistical analysis. Data are presented as average values ± SEM. One-way ANOVA followed by Dunnett’s postdoc was used to compare groups in the same exposure protocol. Asterisks represent statistically significant differences between the indicated group and its corresponding nonexposed control (; ; ).

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