Photobiomodulation Elicits a Differential Cytokine Response in a Cultured Analogue of Human Skin

Background: The study of photobiomodulation in wound healing is encumbered by limited wound study models. The aim of this study was to investigate the efficacy of a 3-dimensional dermal tissue culture model as a cost-saving alternative to conventional photobiomodulation study techniques. Methods: Nine dermal analogue tissue cultures were treated for 2 days with sham or 660-nm wavelength of light at either 1.5 or 3 mW/cm(2) of energy. Tissue cytokine mRNA production was assessed by real-time reverse transcription-polymerase chain reaction, and tissue and supernatant protein were evaluated by immunofluorescence, enzyme-linked immunosorbent assay, and Western blot. Results: Photobiomodulation with 660-nm wavelength light induced transcription of IL-1β and IL-6 mRNA and decreased that of IL-8. Tissue protein content of IL-6 and IL-8 was unchanged, whereas supernatant protein content of IL-8 was significantly increased (P = .023) by 1.5 mW/cm(2) treatment. To describe the localization of cytokines between tissue and supernatant, the relative diffusion of each was calculated and found to be 15-fold higher for IL-6 than for IL-8 despite an overall higher concentration of IL-8 in the tissue. Conclusion: In this study, photobiomodulation elicited mRNA and protein changes quantifiable in both the tissue and supernatant. In addition, the use of this advanced culture model allowed for histological assessment and the comparison of “local” versus “circulatory” responses between the tissue and supernatant, respectively.