Avaliação da aplicação extraoral da fotobiomodulação na mucosite oral induzida pelo quimioterápico 5-Fluorouracil: estudo em modelo animal

Abstract

This study focused on evaluating the effect of topical application of extraoral photobiomodulation therapy (PBMT) with infrared light emission, without sedation, for the scarification and PBM of the buccal mucosa stages, before and during the induction of chemo-induced oral mucositis (OM) by 5-Fuorouracil (5-FU) in Wistar rats. It is an animal experimentation study and 50 animals were used. The animals were distributed into three groups: G1 (control, n = 10 - LBI (Low-Level Laser Therapy, switched off - placebo), for twenty days, before and during the development of OM; G2 (n = 20), extraoral PBM with infrared light, prior to OM induction, for 15 days; and G3 (n = 20), extraoral PBM with infrared light, prior to and during OM induction for twenty days. Throughout the experiment, the animals were clinically monitored by measuring body weight and systemic morbidity. The animals were euthanized, and surgical removal of the cheeks was performed for histological analysis. At the time of euthanasia, 5 mL of blood was collected by cardiac puncture for total leukocyte count. Clinically, only the animals in group G3 presented milder side effects, with faster recovery; side effects were observed more markedly in the animals in group G1 (control) and moderately in the animals in group G2. Regarding body weight, the animals in group G3 showed an initial loss of body mass after the 15th day, followed by a gradual recovery from the 22nd day onwards, suggesting a possible therapeutic effect of PBM with infrared light, but with side effects from MO and an improvement in the animals' overall condition. There was a significant difference in the amount of food ingested on the first and 15th day for all groups. After MO induction, G3 consumed more food than the other groups, suggesting that food consumption differed among the groups on all days. Regarding leukocytes, G3 presented the highest average leukocyte count, indicating a more intense immune response, possibly stimulated by the treatment, while the other groups presented more moderate responses, with G1 considered leukopenic. Photomicrographs of the animals in G1 (control) showed histological signs of MO; G2 did not show disruption of the lining epithelium, and the slides from G3 did not show, histologically, MO, maintaining the intact lining epithelial tissue with a thicker thickness than the other groups. It can be concluded and validated that the topical application of FBM in an extraoral manner with infrared light, employing a standardized protocol, before and during chemotherapy, without the need for sedation, under physical restraint for the steps, and contributing to the preservation of oral health and the general well-being of the animals.