High-fluence light emitting diode-red light inhibits cell cycle progression in human dermal fibroblasts

Skin fibrosis is a debilitating feature of several systemic and dermatologic diseases. While current treatment options carry significant risk of side effects and recurrence, high-fluence light emitting diode-generated red light (LED-RL) is an alternative therapeutic that is safe, non-invasive, and accessible. We previously demonstrated LED-RL decreases fibroblast proliferation, a key pathogenic component of fibrosis. However, the cellular mechanism by which high fluence LED-RL modulates fibroblast proliferation is unclear. Herein, we explored the effects of high fluence LED-RL on human dermal fibroblast cell cycle progression. We demonstrate that LED-RL at 640 J/cm² induced significant arrest of cells in G₀ /G₁ compared to temperature-matched control. This was accompanied by a corresponding increase in expression of checkpoint regulator p53 in irradiated cells. These data demonstrate high fluence LED-RL may exert its anti-proliferative effect on fibroblasts by inducing G₀ /G₁ arrest. Further, this study provides insight into the molecular mechanism underlying LED-RL as an anti-fibrotic therapeutic.