Blue LED induced thermal effects in wound healing: experimental evidence in an in vivo model of superficial abrasions

Year: 2017

Authors: Rossi F., Cicchi R., Magni G., Tatini F., Bacci S., Paroli G., Alfieri D., Tripodi C., De Siena G., Pavone F.S., Pini R.

Autors Affiliation: Institute of Applied Physics ‘Nello Carrara’, National Research Council, Via Madonna del Piano 10, Sesto Fiorentino, I-50019, Italy; National Institute of Optics, National Research Council, Via Nello Carrara 1, Sesto Fiorentino, I-50019, Italy; European Laboratory for Non-linear Spectroscopy (LENS), Via Nello Carrara 1, Sesto Fiorentino, I-50019, Italy; Department of Clinical and Experimental Medicine, Research Unit of Histology and Embriology, Viale Pieraccini 6, Florence, I-50139, Italy; Light4Tech Firenze S.r.L., Via Pisana 316, Scandicci (FI), I-50018, Italy; Department of Physics, University of Florence, Via G. Sansone 1, Sesto Fiorentino, I-50019, Italy

Abstract: A faster healing process was observed in superficial skin wounds after irradiation with a blue LED (EmoLED) photocoagulator. EmoLED is a compact handheld device, used to induce a thermal effect and thus coagulation in superficial abrasions. We present the results of an in vivo study, conducted in a mouse model, to analyze the induced wound healing. Two superficial abrasions were produced on the back of the mice: one area was treated with EmoLED (1.4 W/cm2, 30 s treatment time), while the other one was left naturally recovering. During the treatment, a temperature around 40-45°C was induced on the abrasion surface. Mice back healthy skin was used as a control. The animals underwent a follow up study and were sacrificed at 0, 1, 3, 6, 9, 12, 18, 21, 24 hours p.o. and 6 days p.o. Samples from the two abraded areas were harvested and examined by histopathological and immunofluorescence analysis, SHG imaging and confocal microscopy. The aim of the study was to investigate the inflammatory infiltrate, mastocyte population, macrophage subpopulation, fibroblasts and myofibroblasts. Our results show that soon after the treatment, both the inflammatory infiltrate and the M1 macrophage subpopulation appear earlier in the treated, compared to a delayed appearance in the untreated samples. There was no alteration in collagen morphology in the recovered wound. This study confirms the preliminary results obtained in a previous study on a rat model: the selective photothermal effect we used for inducing immediate coagulation in superficial wounds seems to be associated to a faster and improved healing process.

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More Information: The research leading to thew results has received funding from Tuscany Region and EU PP7 DiopholonicaPlus projects “LihgTPatch (Led Technology in Photo Haemostasis) and “LITE” (Laser imaging of The Eye), from the European Union Seventh Frammoark Programme (FP7/2007-20l3) under grant agreement number 284464, from the Italian Ministry For Education, Ureversity and Research In the framwork of the Flagship Project NANOMAX, from Fondazione Pisa, and from Elite Cases di Risparmio di Firenze.
KeyWords: Cell culture; Coagulation; Fibroblasts; Macrophages; Mammals; Tissue; Tribology, Blue LEDs; Collagen morphology; Experimental evidence; Immunofluorescence analysis; Induced thermal effects; Photocoagulation; Photothermal effects; Wound healing, Abrasion