MOLECULAR MECHANISM OF PHOTOBIOMODULATION ASSOCIATED WITH FIBROBLASTS

(PBM) previously called low intensity laser irradiation (LILI) is a safe and efficient mechanism used to stimulate a positive response through absorbed light (coherent light) or light emitting diodes (LED-non-coherent light), and to reduce pain and inflammation promoting healing of the wound area. PBM has been in existence for over 50 years; however, it is still not widely accepted due to the lack of understanding of the cellular and molecular mechanisms in various cells including fibroblasts. The mechanism of action of PBM with fibroblasts assumes that light is absorbed by mitochondrial chromophores to initiate cellular responses. The photons released dissociate inhibitory nitric oxide to increase electron transport, adenosine triphosphate (ATP) production and mitochondrial membrane potential (MMP). Furthermore, ion channels are activated and allows calcium to enter the cells and stimulate various signaling pathways leading to the activation of transcription factors which affect the protein expression, anti-inflammatory signaling, redox reactions, cell death mechanism, as well as stimulate processes to increase cell proliferation of various cell types, macrophage phagocytic activity, locomotion and maturation of fibroblasts. PBM decreases the inflammatory infiltrate, stimulating fibroblast proliferation and angiogenesis, and therefore recommended for wound healing processes. This chapter will summarise the molecular mechanisms of fibroblasts induced by PBM, reviewing current therapeutic approaches.