Photodynamic therapy for the treatment of buccal candidiasis in rats

Objective: evaluate the effects of photodynamic therapy on buccal candidiasis in rats. Methods: Seventy-two rats negative for the Candida genus in the buccal cavity were included in the study. The rats were administered a solution of 0.1% tetracycline hydrochloride in their drinking water and inoculated with suspension of C. albicans for 3 consecutive days. After 7 days, the rats were distributed into 4 groups according to treatment: treated with laser and methylene blue photosensitizer (L+P+); treated only with laser (L+P-); treated only with photosensitizer (L-P+); not treated with laser or photosensitizer (L-P-). A Gallium arsenate-Aluminum laser was used at a wavelength of 660 nm, 50 mW potency and an energy density of 26 J/cm². The rats were submitted to euthanasia immediately, 1 or 5 days posttreatment for microscopic analysis of the tongue dorsum. Semiquantitative analyses were performed in order to assess the degree of epithelium colonization by Candida and the intensity of the tissue lesions. The results were analyzed by Kruskal-Wallis and Bonferroni tests. Results: observation verified that the photodynamic therapy group (L+P+) exhibited fewer epithelial alterations and a lower chronic inflammatory response compared to L-P-. The group L+P- presented more intense epithelial alterations and chronic inflammatory response than the remaining groups. The L-P+ group showed tissue lesions similar to L-P-. Conclusion: rats treated with photodynamic therapy developed more discrete candidiasis lesions compared to the remaining groups.