Cinética da expressão de citocinas no ligamento peridontal e fluido crevicular gengival após a aplicação de força ortodôntica

Abstract

Mechanical loading with orthodontic appliances induces activation of pathways and release of mediators that promote remodeling of periodontal tissues. Among these, cytokines are associated with different mechanisms in the periodontal remodeling process. The aim of this study was to: (i) assess the level of cytokines in the periodontal ligament (PDL) and gingival crevicular fluid (GCF) in response to orthodontic force; (ii) verify if there is a correlation in production of cytokines in PDL and GCF. 23 patients were included in this split-mouth study. A total of 68 premolars were included. While one premolar subjected to 0,980 N force for a specified period (days 1, 3, 7, 14, 21 and 28), the contralateral teeth were used as controls. Before surgery, GCF samples were collected and, after extraction, the PDL. Then, samples were analyzed for cytokine levels [Interleukin-2 (IL-2), Interleukin-4 (IL-4), Interleukin-6 (IL-6), Interleukin-10 (IL-10), Interleukin-17A (IL-17A), Tumor necrosis factor-alfa (TNF-) and Interferon-gama (IFN-)] by Cytometric Bead Array. Mechanical loading was not able to induce significant changes from most of cytokines investigated in PDL or GCF. However, after force application, increased expression of IL-6 in PDL (on day 1 after force application), and reduced expression of IL-6 in GCF (on day 21) were observed. Significant strong positive correlation between GCF and PDL in experimental group was seen on days 3 (IFN-), 7 (IL-10), 14 (IL-17A), 28 (IL-17A, TNF- ) and significant negative strong correlation on days 14 (IFN-) and 21 (IL-2, IL-10). This data suggest there is no clear direct correlation regarding the molecular release in PL for the contribution on the composition of GCF. Furthermore, mechanical stress has induced a differential expression of IL-6 in PDL and GCF.