Use of adipose derived stem cells accelerates the healing process in third-degree burns

Burns are defined as a traumatic injury, usually of thermal origin, that affects the epithelial and adjacent tissue and is classified according to the depth reached. Tissue repair involved in this type of injury is often a challenge both due to its severity and the multiplicity of complications. Regenerative medicine has focused on the use of low-level laser photobiomodulation therapy (LLLT) and adipose-derived stem cells (ADSC), especially in the early stages of the process, to promote better healing and shorten repair time. Therefore, aim of this study was to evaluate the action of LLLT (660 nm) and ADSC in the repair process of burned skin tissue and investigate the association of the techniques (LLLT and ADSC).

An in vivo study was carried out using 96 rats (Wister) with a scald burn model at a temperature of 95ºC, exposing the animal's back for 14 s. Animals were randomized into seven groups and three periods, five, 14 and 21 days. The groups included GC: Control group, ADSC-: Group treated with CD49d negative cells, ADSC+ : Group treated with positive CD49d cells, CULT: Group treated with conventional isolation cells, LLLT: Group treated only with LLLT Low Power Laser, ADSC-LLLT: Group treated with CD49d negative cells and LLLT. ADSC+LLLT: Group treated with positive CD49d cells and LLLT. The groups treated with LLLT (660 nm; 5 J/cm2) received irradiation three times a week, on alternate days for five, 14 and 21 days, according to the time of biopsy. ADSC-treated groups received one to three applications of the cells in a total volume of 1000 μL starting soon after the surgical debridement of the burn. Photographic monitoring was carried out at 5, 14 and 21 days after the beginning of the experiment to assess the degree of lesion contraction. Macroscopic, morphometric and histopathological analyzes were performed.

We showed significant re-epithelialization as well as an improvement in the healing process in the ADSC+, LLLT and ADSC+LLLT groups. We observed effects in the reduction of the inflammatory phase, increase in angiogenesis, decrease in oedema, greater collagen deposition, and better organization of the extracellular matrix compared to the other treatments. Moreover, the immunomagnetic separation of ADSC cells through the expression of the CD49d protein proved to be a useful means to obtain a more homogeneous population of cells with a role in tissue regeneration compared to the ADSC- and CULT groups.

In conclusion, the association of ADSC+ with LLLT was effective in accelerating the burn repair process, stimulating cell proliferation and formation of more normal skin tissue.