Protocolo para uso do laser diodo terapia de baixa potência combinando comprimentos de ondas vermelhas e infravermelhas em feridas cutâneas experimentais em ratos wistar

Abstract

The low-level laser has been used for many years as a therapeutic resource for skin wound healing, basing on cellular energy uptake and increasing in mitosis and protein synthesis. Among the published studies on the topic, one must highlight the good results presented when red and infrared wavelengths are combined for skin wound healing. However, there is still a need to standardize the setting parameters for this therapy with laser, specially the fluency, which aggregates several outcomes such as energy, power, time and irradiation area. The proposal of the present experiment is to find, within a fluency range, the best dosage that can hasten skin wound repair. We used 60 rats divided, randomly, into four groups: Group A, without irradiation, and three intervention groups which received Low-Level Diode Laser Therapy combining two wavelengths (660nm and 808nm), using the same power (100mW), but with different fluencies, which dosages were equally divided for each wavelength used as follows: Group B (20J/cm2), Group C (60J/cm2) and Group D (120J/cm2). Each group was assessed with three (3), seven (7) and fifteen (15) days. Animals went through surgery in order to make a dorsal wound with the use of a nº8 dermatological punch. These wounds were exclusively treated on intervention groups, however, all wounds were quantitatively assessed with biometry of wound closure; measurements and counting of histological structures were also performed for all wounds through morphometric and stereological analysis. Intervention presented significant results for the relative wound area retraction (Group D3: 43,13%, p=0,02), collagen fibers volume density (Group D15: 53,44%, p=0,0001) and angiogenesis with the increasing in blood vessels density area profile (Group D3: 0,008/μm2 and Group C3: 0,007/μm2, p=0,001) and blood vessels length (Group D3: 0.017μm/μm2 and Group C3: 0.016μm/μm2, p=0,0007). The fluency of 120J/cm2, used on Group D, in this experiment, showed as the best fluency dosage to accelerate the healing of skin wounds.