After irradiation with a blue LED light photocoagulator, a faster healing process is observed in superficial skin wounds. This device has been used in order to induce a thermal effect and haemostasis in superficial abrasions. Our previous in vivo study in rat and mouse models focused on the inflammatory phase within the healing process, showed a light-induced modulation, which leads to a shortened healing time and to a better recovery of the dermal tissue. Here we describe a new series of experiments that have been conducted producing two superficial abrasions on the shaved-back of mice, treating the one wound with the blue light and leaving the other one healing without any treatment. The healthy skin was used as a control. The animals were observed during healing and sacrificed at different and selected time points. Wound tissue samples have been harvested both from the treated and untreated areas and examined by histopathological and immunofluorescence analysis, SHG imaging, and confocal microscopy. The results of the study point out the interaction among different cells type and the collagen morphology restoration as obtained in different pathological mice models treated with blue LED light.
Blue LED light irradiation is currently under investigation because of its effect in wound healing improvement. In this context, several mechanisms of action are likely to occur at the same time, consistently with the presence of different light absorbers within the skin. In our previous studies we observed the wound healing in superficial abrasions in an in vivo murine model. The results evidenced that both inflammatory infiltrate and myofibroblasts activity increase after irradiation. In this study we focused on evaluating the consequences of light absorption in fibroblasts from human cells culture: they play a key role in wound healing, both in physiological conditions and in pathological ones, such as keloid scarring. In particular we used keloids fibroblasts as a new target in order to investigate a possible metabolic or cellular mechanism correlation. Human keloid tissues were excised during standard surgery and immediately underwent primary cell culture extraction. Fibroblasts were allowed to grow in the appropriate conditions and then exposed to blue light. A metabolic colorimetric test (WST-8) was then performed. The tests evidenced an effect in mitochondrial activity, which could be modulated by the duration of the treatment. Electrophysiology pointed out a different behavior of irradiated fibroblasts. In conclusion, the Blue LED light affects the metabolic activity of fibroblasts and thus the cellular proliferation rate. No specific effect was found on keloid fibroblasts, thus indicating a very basic intracellular component, such as cytochromes, being the target of the treatment.