Differing energy densities with laser 670nm InGaP controls inflammation and collagen reorganization in burns

Purpose: This study compared different energy densities of laser on second degrees burns in rats aiming to determine the most effective dosimetry in stimulation of the healing process. Methods: Burns were induced in the dorsal skin of 54 animals divided into three groups (n: 18): 1-without treatment; 2-irradiated lesions by the Indium Gallium Phosphide (InGaP) 670nm (4.93J/cm(2)) laser; 3-irradiated lesions by the InGaP-670nm (9.86J/cm(2)) laser. Samples were collected on the 2, 10 and 18 days after injury for structural, morphometry, biochemical analysis and Western blotting. Results: The energy densities examined were effective in significantly increasing the total number of fibroblasts and blood vessels and reduce the number of inflammatory cells particularly in irradiated lesions with 9.86J/cm(2). This same energy density significantly increased the amount of GAGs (Glycosaminoglycans), decreased the TGF-beta 1 (Transforming Growth Factor beta 1) and increased the VEGF (Vascular and Endothelial Growth Factor) during the experimental period. This energy density also significantly increased the Collagen type I and decreased Collagen type III and the active isoform of metalloproteinase 9 (MMP-9). Conclusions: The energy density of 9.86J/cm(2) was more effective in promoting cellular responses related to neoangiogenesis, decreasing inflammation and collagen fibers reorganization. (C) 2017 Elsevier Ltd and ISBI. All rights reserved.