Terapia fotodinâmica antimicrobiana adjuvante com azul de metileno / etanol na periodontite experimental em ratos diabéticos: resposta inicial - 7 dias

Abstract

In vitro evidences suggested methylene blue (MB) diluted in ethanol improves the antimicrobial photodynamic therapy (aPDT) effect. We hypothesized that aPDT with MB dissolved in ethanol 20% could limit periodontal destruction provoked by ligature in diabetic rats when compared to SRP and aPDT using MB/water. Forty adult male rats received intraperitonial injections of streptozotocin. After 14 d, 5 animals were allocated in the CG, and 35 animals received ligature at the first mandibular molar. After 7 d, the ligature was removed and the animals were randomized into 4 groups: LG (without treatment); and SRPG (SRP), aPDTW (SRP and aPDT with MB 100μg/ml dissolved in water), and aPDTEt (SRP and aPDT with MB 100μg/ml dissolved in water, ethanol and carboxymethylcellulose (77:20:3)). Animals were euthanized at 7 d. Histometric and hematological values were statistically analyzed. The animals percentage presented mild and severe inflammatory infiltrate was: 10% and 40% for SRPG; 20% and 30% for aPDTW; and 50% and 0% for aPDTEt, respectively. SRPG presented statistically higher count of WBC, lymphocytes and monocytes than all the other groups. For bone loss (BL), no statistical difference was observed among aPDTEt (0.08±0.03) and aPDTW (0.21±0.15); and among aPDTW and SRPG (0.30±0.18). aPDTEt BL was significantly lower than SRPG. aPDT, independently of the formulations, showed BL statistically similar to the animals without periodontitis. aPDTEt animals showed collagen content significantly higher than untreated animals (LG), and presented higher mean values than animals without periodontitis, even so the differences don‟t were statistically significant. Collectively, our findings showed aPDTEt presented most promising results, followed for the aPDTW and SRP.We concluded that adjunctive aPDT using MB solubilized ethanol could be an alternative to periodontal treatment in patients who has diabetes. Then, we suggest further studies with more complex animals models and with higher follow-up to confirm our initial findings.