BLUE LED LIGHT TO PROMOTE WOUND HEALING IN DIFFERENT MICE MODELS

Aim: Demonstrate the efficacy of the photobiomodulation by blue LED light (BLL) in promoting the wound healing process. Method: Two abrasions were produced on the back of the mice: one area was treated with BLL (420nm, 1.4W/cm2, 30s), the other one was left naturally recovering. The animals were sacrificed after 0, 3, 6, 9, 18, 24h. Samples from the two areas were harvested and inflammatory infiltrate and the major cell types involved in wound healing process were investigated by histology, immunohistochemistry and biochemical assay. In other groups of animals, one or two full thickness wounds were performed to study the effects of the BLL in a mice model of chronic wound. Results / Discussion: We demonstrate that the application of 30s of BLL induces an early increase of inflammatory cell infiltrate, mast cells degranulation and high level of macrophages M2 subpopulation in treated tissue. Our study in vivo model of chronic wound, show that the BLL also affects pro-MMP-9 and MMP-2. We suppose that at early times after the wound induction, the BLL induces an increase of matrix degradation to prepare the wound bed to collagen deposition while, at later time, this increase may become an indicator of the angiogenetic process. Conclusion: The BLL can be used to promote healing in acute and chronic wounds. Our observations demonstrate that BLL induces an improvement of the healing process allowing an early onset into the inflammatory phase, and overall the reduction of the healing time in skin wounds.