Evaluation of Photodynamic Therapy effect on oral mucosa of rats

Objective: In previous study, the Photodynamic therapy (PDT) mediated by photogem ® (FS) and blue LED inactivated suspension cultures of C. albicans and C. glabrata, however, it is important that it does not cause adverse effects to the tissues. Thus, the purpose of this study was to determine the effects of irradiation on the oral mucosa of rats with blue LED (460 nm and power 50mW/cm2) in the presence of photosensitizer (500 mg/L). Methods: 60 rats were (Rattus norvegicus Holtzman Albinus) divided into: G1 - control group, G2 - FS (500mg / L) + LED, G3 - FS (500mg / L) without LED, G4 - distilled water + LED. Then, the animals were anesthetized and mucosal palate treated with FS for 30 minutes (pre-incubation) and irradiated for 20 minutes. Photographs were taken for analysis macroscopic following these evaluation periods: 0 h, 24 h, 3 day and 7 days after the treatments. Next, following these periods, the animals were sacrificed and the palate was removed for analysis by light and fluorescence microscopy. Results: In the macroscopic analysis, it was observed that none of the animals, regardless of group, showed any noticeable change in the mucosa of the palate. In the histological analysis, it was observed that in the group (G2) the tissue had normal appearance, except by a discontinuity of the layer of keratin. Furthermore, in other experimental groups (G3 and G4), the tissue showed similar appearance to the control group (G1). In the fluorescence microscope, Photogem could be detected only in the epithelium. In the connective tissue, were not observed signs of fluorescence. Conclusion: Photogem was present only in the epithelium and the PDT caused slight microscopic change in oral tissues of animals, at concentration evaluated.