Avaliação da fotobiomodulação na reparação de feridas cutâneas: Estudo clínico e histológico em ratos

Abstract

Skin sores are considered a public health concern due to their high occurrence rate among the population. Low-level laser therapy (LLLT) with different wavelengths is one of the novel therapies that focus on speeding up and optimising these injuries’ healing process. The goal of this study is to evaluate the tissue reparation from secondary intention wound healing in rats through clinic and histopathologic parameters. This research was sent to and approved by the Ethical Animal Use Commision (CEUA) of the State University of Paraíba (UEPB) in Campina Grande-PB. In this study, 60 male albino rats of the Wistar lineage were used. Each of these animals weighed approximately 250g and was 10 weeks old. The animals were anaesthetised and subjected to an excisional skin wound in the dorsal region measuring 0.6mm in diameter and four experimental groups were formed through simple randomization. The groups were: the Control Group (simulated treatment with a turned-off device), the Red Group (λ=660 nm, 100 mW, 1J per stitch, 10 second) (n=15); the Infrared Group (λ=808 nm, 100 mW, 1J per stitch, 10 seconds) (n=15); the Combined Group: Red and Infrared (λ=660 nm, 100 mW, 1J + λ=808 nm, 100 mW, 1J) (n=15): irradiated simultaneously, with subgroups of 5 animals for each eutanasia period (03, 07, and 14 days after the wound). The therapy sessions occurred immediately after the wounds were introduced and were repeated every 48 hours, except on the day the animal was euthanized. After the animals were euthanized, in their respective predefined days, the Wound Contraction Index (WCI) was evaluated, the specimen was removed, and its tissue cuttings were submitted to hematoxylin-eosin (HE) and toluidine blue (TBO) staining. The largest wound retractions occurred in the 14-day period, compared to the other periods analysed. Moreover, the amount of inflammatory cells decreased at the end of the period evaluated, the number of mastocytes varied, and the re-epithelialization process in the groups was also completed at the 14-day mark.