High-Fluence Light-Emitting Diode–Generated Red Light Modulates the Transforming Growth Factor-Beta Pathway in Human Skin Fibroblasts

BACKGROUND Skin fibrosis is a significant medical problem with limited available treatment modalities. The key cellular characteristics include increased fibroblast proliferation, collagen production, and transforming growth factor-beta (TGF-B)/SMAD pathway signaling. The authors have previously shown that high-fluence light-emitting diode red light (HF-LED-RL) decreases cellular proliferation and collagen production. OBJECTIVE Herein, the authors investigate the ability of HF-LED-RL to modulate the TGF-B/SMAD pathway. MATERIALS AND METHODS Normal human dermal fibroblasts were cultured and irradiated with a commercially available hand-held LED array. After irradiation, cell lysates were collected and levels of pSMAD2, TGF-Beta 1, and TGF-Beta I receptor were measured using Western blot. RESULTS High-fluence light-emitting diode red light decreased TGF-Beta 1 ligand (TGF-B1) levels after irradiation. 320 J/cm2 HF-LED-RL resulted in 59% TGF-B1 and 640 J/cm2 HF-LED-RL resulted in 54% TGF-B1, relative to controls. 640 J/cm2 HF-LED-RL resulted in 62% pSMAD2 0 hours after irradiation, 65% pSMAD2 2 hours after irradiation, and 95% 4 hours after irradiation, compared with matched controls. High-fluence light-emitting diode red light resulted in no significant difference in transforming growth factor-beta receptor I levels compared with matched controls. CONCLUSION Skin fibrosis is a significant medical problem with limited available treatment modalities. Light-emitting diode–generated red light is a safe, economic, and noninvasive modality that has a body of in vitro evidence supporting the reduction of key cellular characteristics associated with skin fibrosis.

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