Abstract

Skin is the largest organ of the body, responsible for thermoregulation and barrier against external agents, including bacteria. Wounds cause loss of skin integrity and can also lead to severe pathologies. For these reasons, efficient treatment of skin wounds is necessary, especially when they become chronic or appear in subjects with comorbidity. Blue LED light photobiomodulation is successfully used in wound management. Although the mechanism of action is still unclear, many studies have been conducted, and some target molecules of blue light are unanimously recognised. Among them, Cytochrome C oxidase is included. For this reason, mitochondria represent a target organelle for blue light radiation. Mitochondria are involved in redox signaling and in maintaining the balance of reactive oxygen species (ROS), essential for several vital functions such as calcium homeostasis. Therefore, studying the effects of blue light on mitochondria may be helpful in identifying a therapeutic dose exploitable in clinical practice. Whit this purpose, primary cultures of human dermal fibroblasts were obtained, and a blue LED light device (410-430 nm in emission, 1 W optical emission power) was used. Three doses of blue light (4, 21, 42 J/cm²) were applied once. Electron microscopy was used to reveal mitochondrial morphology before and after irradiation, while confocal microscopy was used to reveal ROS concentration. Our results demonstrated that blue light stimulates ROS dose-dependently, and mitochondria are subject to morphological changes. Future studies will be devoted to determining whether the change in morphology is also related to changes in function.

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