Background: Light-emitting diode-generated blue light (LED-BL) is part of the visible light spectrum that does not cause DNA damage and may represent a safer alternative to ultraviolet phototherapy. Previous research demonstrated that LED-BL can inhibit adult human skin fibroblast proliferation and migration speed and is associated with increased reactive oxygen species (ROS) generation in a dose-dependent manner. In addition, resveratrol possesses potent intracellular antioxidative effects on ROS-free radicals in human skin fibroblasts.
Objective: The authors studied the effects on migration speed as a surrogate to measure LED-BL effects on fibroblast function. The authors hypothesized that resveratrol, a potent scavenger of ROS, could prevent the effects of LED-BL on fibroblast migration speed. This would implicate ROS as the mechanistic driver of LED-BL effects on human skin fibroblasts.
Methods: To demonstrate that resveratrol could prevent the effects of LED-BL (415-nm), fibroblasts were incubated with resveratrol (Sigma-Aldrich, St. Louis, MO) at concentrations of 0.001% and 0.0001% for 24 hours and then irradiated with LED-BL at fluences of 30, 45, and 80 J/cm. Postirradiation fibroblast migratory speed was assayed in an environment-controlled computer-assisted video microscopy system. Reactive oxygen species levels were measured by flow cytometric analysis of dihydrorhodamine. Statistical analyses with analysis of variance and Student t-test were performed to compare individual treatment arms and matched controls.
Results: The experimental results demonstrate that pretreatment of skin fibroblasts with resveratrol at concentrations of 0.001% and 0.0001% prevents the effects of 30, 45, and 80 J/cm of LED-BL on fibroblast migration speed. The authors found that LED-BL at a fluences of 30, 45, and 80 J/cm significantly increased ROS, whereas pretreatment with 0.001% resveratrol significantly reduced ROS generation.
Conclusion: The findings demonstrate that LED-BL-induced decreases in fibroblast migration speed can be prevented by pretreating cells with resveratrol. This finding supports the hypothesis that ROS generation is the most likely driver of LED-BL-induced alterations in migration speed and suggests that ROS generation may be responsible for a number of other alterations seen after LED-BL phototherapy, such as decreases in cellular migration, cytokine levels, and myofibroblast differentiation. The authors hypothesize that their findings may result in greater understanding of the fundamental mechanisms underlying visible light interaction with skin and they hope dermatologists and other researchers may use these pathways for patient benefit.