Fotobiomodulação por laser de baixa potência com duplo comprimento de onda em feridas crônicas

Abstract

The aim of this study was to evaluate the effects of photobiomodulation (FBM) by dual-wavelength low-power lasers on the healing and bacteria bioburden of pressure ulcer (PU) models. Then, case series is evaluating the therapeutic efficacy of dual-wavelength low-power lasers treatment of chronic wounds. Twenty-five male Swiss mice were divided into five equal groups. Ischemia reperfusion cycles were employed to cause PU formation by the external application of magnetic plates. Immediately after wounding, a suspension of Pantoea agglomerans was applied at the base of all the wounds of the infected groups, using a calibrated pipette. FBM (simultaneous emission at 660 and 808 nm, 142.8 J/cm², in continuous wave emission mode) was applied to the PUs for 14 sessions. The animals were euthanized 14 days after PU induction and their tissues were analyzed for wound contraction and reepithelialization, epidermis thickness, bacterial survival, IL-1β, and IL-10 mRNA relative level evaluations. The PU areas appeared larger in the mice from the infected groups than in those in the laser groups 4 days after PU induction, and presented incomplete reepithelialization 14 days after PU induction. However, the FBM accelerated the wound healing in the infected + laser groups compared to the infected groups 11 and 14 days following the PU induction. The infected and irradiated PUs exhibited a thinner neo-epidermis than those in the infected groups, and the bacterial survival decreased in the laser groups; the IL-1β mRNA levels demonstrated an increasing tendency while the IL-10 mRNA levels demonstrated a decreasing tendency in the infected + laser and laser groups. These results suggest that FBM improves healing by killing or inhibiting bacteria in PUs as well as by accelerating the wound healing, resulting in tissue repair. In addition, based on case series, the findings show that exposure to low power dichromatic lasers was effective to improve healing in chronic wounds, such as the effects induced by infrared and red lasers could be additive.