Blue LED light (420 nm) has successfully been used to induce hemostasis through a photo-thermo-coagulation process: light absorption by hemoglobin triggers a local temperature increase, leading to a coagulation effect. Besides hemoglobin, there are other macromolecules, such as cytochromes, that are able to absorb blue light: after irradiation, these ubiquitous cellular components can trigger one or more intracellular pathway that modulates the healing process, in combination with the coagulation effect. The aim of this study is to investigate the molecular effects of 30s treatment with a Blue LED device in two different murine model wounds. In the first model we studied a superficial wound, and in particular the inflammatory response by an immunohistochemical and morphological analysis of the many cellular types involved in this phase of the healing process. The second model is a full-thickness wound: a customized ELISA kit enabled to study EGF, bFGF, VEGF, TNF-α, MMP-2 and PRO-MMP-9 at different postoperative time points (1, 3, 6, 9, 24 hours and 7 and 14 days after the treatment). A modulation of these parameters was evidenced in the early phase of the wound healing process, while at longer follow up times no differences are pointed out.
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÷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.