Low-intensity red laser on the prevention and treatment of induced-oral mucositis in hamsters

Objective: The purpose of this study was to investigate the effects of laser phototherapyas preventive and therapeutic regime on induced-oral mucositis in hamsters. Design: The animals were divided into four groups: preventive cryotherapy, preventive laser, therapeutic laser and therapeutic control group. mucositis Was induced in hamsters by intraperitoneal injection of 5-fluorouracil (5-FU) and superficial scratching. All preventive treatment was performed oil the right cheek Pouch mucosa. The left Pouch mucosa was used for a spontaneous development of mucositis and did not receive any preventive therapy. Laser parameters were: lambda = 660 nm, P = 30 mW, D = 1.2 J/cm(2), Delta t = 40 s, spot size 3 mm(2), l = 1 W/cm(2). Cryotherapy was done positioning ice packs in the hamster mucosa 5 min before 5-FU infusion and 10 min afterward. To study the healing of mucositis, the left pouch mucosa of each of the hamsters in the TLG received laser irradiation on the injured area. Irradiation parameters were kept the same as abovementioned. The control hamsters in the TCG did not receive any treatment. The mucositis degree and the animal's body mass were evaluated. Ail assessment of blood vessels was made based oil immunohistochemical staining. Results: The CC animals lost 15.16% of theirs initial body mass while the LG animals lost 8.97% during the first 5 days. The laser treated animals had a better clinical outcome with a faster healing, and more grnaulation tissue. The quantity of blood vessels at both LG and CC were higher than in healthy mucosa. Regarding the therapeutic analysis, the severity of the mucositis in the TLG was always lower than TCG. TLG presented higher organization of the granulation tissue, parallel collagen fibrils, and increased angiogenesis. Conclusion: The results Suggest that laser phototherapy had a positive effect in reducing mucositis severity, and a more pronounced effect in treating established mucositis. (C) 2008 Elsevier B.V. All rights reserved.