Efeito da terapia fotodinâmica como tratamento complementar para periodontite apical em modelo experimental de asma

Abstract

Apical periodontitis is caused by pulpal necrosis, with consequent inflammation and destruction of the periapical tissues. Bacteria are able to survive and maintain the periapical infectious process despite the therapeutic measures applied in cases of well-conducted endodontic treatment, especially Enterococcus Faecalis. It has been shown that periodontal disease can influence the symptoms of asthma. Approximately 350,000 hospitalizations occur in Brazil annually caused by this pulmonary disease, being the fourth cause of hospitalizations by the Unified Health System, the third among young people and children. Asthma is a chronic inflammatory disease characterized by lower airway hyperresponsibility and variable airflow limitation. To date, there are few papers correlating the symptoms of asthma in patients with apical periodontitis. The objective of this study was to evaluate photodynamic therapy as a complementary treatment in apical periodontitis in an experimental model of asthma. Sixty four male Balb/C mice and apical periodontitis was induced for 21 days without treatment and asthma by administration of ovalbumin (OVA) and aluminum hydroxide, subcutaneously (days 0 and 14), and gold tracheal three times a week for 5 weeks. Endodontic treatment was performed with mechanical instrumentation, calcium hydroxide and photodynamic therapy (PDT). A diode laser, 660nm wavelength, exposure time 90 seconds, was used with methylene blue as a photosensitizer for photodynamic therapy. After euthanasia the inflammatory mediators pattern was evaluated through the production of IL-4, IL-5, IL-6, IL-1β, TNF-γ and IL-10 of bronchoalveolar lavage and pulmonary explant using the Elisa method. For statistical analysis, ANOVA was used, followed by a post-test and considered significant with p <0.05. The results showed that apical periodontitis, as well as asthma, increases the cytokine IL-4, IL-5, IL-6, IL-1β, TNF-γ and IL-10 levels. When associated, there was an increase in the release of IL-6 and a reduction in cytokine levels IL-4, IL- 5 and IL-10. On the other hand both conventional and PDT associated endodontic treatment was able to decrease the release of IL-4, IL-5, IL-6, IL-1β, TNF-γ cytokines and increase IL-10 levels. We conclude that apical periodontitis can cause pulmonary inflammation and that the association with asthma exacerbates the process. However, PDT reversed this increase in the release of inflammatory mediators.