Avaliação do efeito da terapia fotodinâmica antimicrobiana com curcumina na reabsorção óssea periodontal em ratos diabéticos por meio da microtomografia computadorizada

Abstract

Periodontitis is characterized by bone loss and has a bidirectional relationship with diabetes. The aim of this study was to evaluate the effect of antimicrobial photodynamic therapy (aPDT) with curcumin on reducing periodontal bone resorption in diabetic rats using microcomputed tomography (micro CT). An in vivo experimental study was conducted using 80 male rats from the Rattus norvegicus species, class Mammalia, order Roedentia, Wistar lineage, aged 60-90 days and mass of 250-350 grams. Animals were divided into two groups: 40 normoglycemic (NG) and 40 diabetic (DM), being subdivided into 4 groups according to treatment: GI: non-surgical periodontal therapy (GI-NSPT); GII: NSPT + curcumin gel 2% (GII-CURC); GIII: NSPT + LED (GIII-LED); GIV: NSPT + aPDT (GIV-PDT). Diabetes was chemically induced by intraperitoneal injection of a single dose of 50mg/kg of streptozotocin. Animals that presented alterations in the glycemic index in all stages (glycemia ≥ 250mg/dL) were selected for the diabetes group. Periodontitis was induced with ligation around the first lower molar for 7 days. At the end of interventions, five animals from each group were euthanized at 7 and 14 days and the hemimandibles were removed for analysis of alveolar bone loss, by microCT through quantitative analysis of linear and volumetric measurements using DataViewer® software (SkyScan®). For intragroup evaluation, two-way ANOVA and the t test for independent samples were used. The results of measurements of linear bone loss in NG and DM animals showed that there was no difference among treatments. In the intragroup analysis, GII-CURC showed in NG rats less bone loss in the furcation region at 14 days (1,357.68 to 795.74) and for DM rats on the vestibular face show increase in bone loss (788.70 to 1,487.22) with significant difference was observed when compared to the group with 7 days of treatment. Regarding the volumetric analysis of NG rats, the lowest values related to bone remodeling were recorded for GIV-PDT, and in the intragroup analysis, significant differences were for G-II with lower tissue volume at 14 days (1.69 to 0.87), despite showing increase in the trabecular number (1.68 to 4.16) and decrease in its separation (0.59 to 0.25). In DM rats, there was no difference between treatments with 7 and 14 days. GIII-LED and GIV-PDT groups showed significant differences in the intragroup analysis, with increased bone surface area (2.17 to 10.84 and 3.97 to 8.66, respectively) and trabecular thickness at 14 days (0.07 to 0.11 and 0.08 to 0.11, respectively). In the comparison between DM and NG animals with respect to linear measurements, GII-CURC showed greater bone loss in the interproximal region at 7 days in NG rats and at 14 days in DM rats. As for volumetric measurements, showed differences in some parameters at both times, with no preference for NG or DM rats. It could be suggested that for NG rats, complementary therapies could lead to additional benefits by the mechanism of action against bacteria and in favor of bone remodeling by immunomodulating the host response. For DM rats, periodontal treatment could be suggested, starting with aPDT and curcumin and maintenance with repetition of aPDT, LED or NSPT sessions. In the comparison between NG and DM rats, the systemic condition did not have much influence on periodontal bone loss.