Blue light effects in human keloid fibroblasts

Keloids scars are an abnormal overgrowth of fibrotic tissue in response to an injury. The current treatments show several limits and do not represent a definitive solution or a prevention protocol. In a preliminary study, we irradiated two samples of human keloid fibroblasts with a Blue LED light, evidencing a possible modulation of their activity in vitro. In the current study, we use primary fibroblasts cultures from eight keloid tissues (from seven selected patients undergoing aesthetic surgery). The fibroblasts were irradiated with a Blue LED light and the treatment time was varied in the range 5 divided by 60s. After irradiation, cell metabolism and cell proliferation were studied by the use of two colorimetric tests, CCK-8 and SRB (Sigma-Aldrich, Saint Louis, Missouri, USA). The analysis was performed 24 and 48h after the treatment. We thus evidenced that the Blue LED light induces a modulation of the fibroblasts metabolism; this effect is particularly evident at 30s irradiation time. We also evaluated the impact of Blue LED light on membrane currents by performing whole-cell patch-clamp recordings. We observed a significant increase of voltage dependent outward currents activated by a depolarizing ramp-protocol upon Blue LED light irradiation (@30s exposure). This effect was maintained in K+ free-solutions, thus ruling out the involvement of K+ channels. In conclusion, we demonstrated that the Blue LED light has a photobiomodulation effect in fibroblasts from human keloids. This effect can be proposed as a possible treatment of the wound site in human patients to prevent keloid scars occurrence.