Avaliação da imunomodulação e eficácia da fotobiomodulação no tratamento da osteonecrose dos maxilares induzida por bifosfonatos em modelo murino

Abstract

This study aimed to evaluate if antimicrobial photodynamic therapy (aPDT) repairs bisphosphonate-related osteonecrosis of the jaw (BRONJ) modulated by the nuclear factor - kappa B (NF-kB) pathway in a murine model. The animals were divided into groups: negative control (NC), positive control (PC), experimental osteonecrosis (ONE) + photosensitizer (PS), ONE + photobiomodulation (PBM), and ONE + antimicrobial photodynamic therapy (aPDT). Over 8 weeks, ONE was induced by administering 250 μg/kg of zoledronic acid to the animals, with 0.9% saline solution being injected intraperitoneally in the NC group. The triggering factor for ONE was the extraction of the lower left first molar. Laser irradiation was performed under red light (wavelength ~660 nm, power 50 mW, energy 2 J, energy dose 66.67 J /cm2, and time 40 s) for 4 weeks. Methylene blue (100 μg/mL) was used as the PS. The animals were euthanized and observed macroscopically for the presence/absence of exposed bone and epithelial repair and microscopically by histochemical and immunohistochemical methods. The macroscopic and histomorphometric data were analyzed by means of one-way analysis of variance and Tukey’s post-test, with a statistical significance level of 5% (p < 0.05), to establish differences among the groups. In the NC, ONE+PS, ONE+PBM, and ONE+aPDT groups, mucosal repair, preserved osteocytes, and immunostaining against NF-kB were observed in the extraction region. The PC group showed no mucosal repair, showing anucleated osteocytes and multifocal immunostaining against NF-kB. In the ONE+PBM and ONE+aPDT groups, a greater deposition of extracellular matrix and lower amount of necrotic bone tissue was found. It is concluded that the use of PBM and aPDT in the treatment of BRONJ was effective for bone and epithelial repair in addition to reducing inflammation. The use of aPDT was effective for bone and epithelial repair and decreased inflammation mediated by the NF-kB pathway in the irradiated regions.