Análise dos mastócitos a fotobiomodulação com diodo emissor de luz (LED) verde e vermelho em queimaduras cutâneas de terceiro grau

Abstract

Burns are skin lesions that trigger an inflammatory response. Mast cells, immune cells, play a central role in this process, synthesizing, storing and releasing potent chemical mediators of the inflammatory process, through their degranulation, affecting wound healing and tissue regeneration. It is known that Laser (light amplification by stimulated emission of radiation) and low power Light Emitting Diode (LED) can modulate the inflammatory process. However, studies evaluating the effects of these photobiomodulation therapies on mast cells are still scarce. Thus, the aim of this study was to investigate the effect of photobiomodulation with green and red LED on mast cells and their subtypes present in third-degree burns. The sample consisted of 75 Wistar rats, divided into three groups: Control (CTRL) (n=25), red LED (VERM) (n=25) and green LED (VERD) (n=25), with subgroups of five animals for each time of euthanasia (7, 14, 21, 28 and 32 days). After burn induction, therapy was performed daily with VERM (630 ± 10 nm, continuous emission, Dose = 9 J/cm², 300 mW, 30 seconds, per point) and VERD (520 ± 30 nm, continuous emission, Dose = 60 J/cm², 180 mW, 30 seconds, per point) in contact with four wound points (total: 36 J/cm², 120 seconds and 240 J/cm², 120 seconds) and in the CTRL there was only treatment simulation. After staining with Toluidine Blue, the three types of mast cells were identified and quantified based on the degree of cell degranulation: Type 1 Mast Cells (MCT1), Type 2 Mast Cells (MCT2), and Type 3 Mast Cells (MCT3), the data were analyzed using the Mann-Whitney test and descriptively, considering a significance level of 5% (p<0.05). In relation to the control group, the irradiated groups showed an increase in the number of total mast cells (total MCT) at 7, 14 and 21 days (p<0.05), corresponding to the initial stages of inflammation, a decrease in the irradiated groups of type mast cells 1 (MCT1) at all time periods when compared to CTRL (p<0.05). The most significant indices were in type 3 mast cells, with intense degranulation, observed in VERM at 7, 14, 21 days (p<0.009) and VERD at 14 days (p<0.009) and 32 days (p<0.028) compared to control, and between VERM and VERD at 7 days (p<0.009). Thus, it was possible to conclude that depending on the period, the red and green LED were effective in the modulation process of mast cell degranulation in burns on the back of rats.