Immune response mediated by Th1 / IL-17 / caspase-9 promotes evolution of periodontal disease.

INTRODUCTION: Periodontitis is characterized by inflammatory mediators beyond T lymphocyte function and phenotype (Th1/Th2/Th17). The clinical diversity in periodontitis makes it difficult to characterize the immune response in patients. This study evaluated the profile of the adaptive immune response in the periodontal disease model. METHODS: 72 rats (Wistar) were divided into a control group (CTL/day 0) and periodontitis (PD15/15 days and PD60/60 days). In the PD15 and PD60 groups, periodontal disease was induced by ligature with a silk thread placed in the cervical region of the upper first molar. After euthanasia, the periodontal tissue was analyzed by flow cytometry (CD4, CD8, CD25, CD44), semi-quantitative RT-PCR (T-bet, GATA-3, RORγt), semi-quantitative RT-PCR and ELISA IFN-γ, TNF-α, IFN-γ, IL-4, IL-6, IL-10, IL-17) and by Western blotting (Caspase-9, PCNA). RESULTS: The number of CD4+CD25+, CD4+CD44+, CD8+CD25+ and CD8+CD44+ cells and expression levels of T-bet and GATA-3 are increased in the PD60 group compared to PD15 and CTL. The RORγ-t gene transcript increased in the PD15 group in relation to PD60 and CTL. The cytokines IFN-γ, TNF-α and IL-17 increased in the PD60 group in relation to PD15. The expression of Caspase-9 was higher in the PD60 group than in PD15. CONCLUSIONS: The results suggest that the evolution of gingivitis to periodontitis is related to the accumulation of activated Th1 cells (IFN-γ and TNF-α) associated with the presence of increased IL-17. Studies with inhibitors of these cytokines in periodontal disease may lead to therapy directed at blocking the inflammatory process in this pathology, interrupting bone loss.

Zoledronic acid and alendronate sodium and the implications in orthodontic movement.

OBJECTIVE: To evaluate orthodontic tooth movement (OTM) in rats treated with two types of bisphosphonates (BPs), alendronate sodium (A) and zoledronic acid (Z). DESIGN: In all, 15 male Wistar rats were randomly divided into three groups. Group OTM+A: orthodontic tooth movement and subcutaneous administration of alendronate sodium (2.5 mg/kg); Group OTM+Z: orthodontic tooth movement and subcutaneous administration of zoledronic acid (0.02 mg/kg), and Group OTM: orthodontic tooth movement and subcutaneous injection of saline. The BPs were administered once a day during 25 days before OTM started and during 10 days of OTM. The left upper first molar was moved with a stainless-steel closed coil spring which delivered an initial force of 0.4N. OTM was measured with a digital caliper comparing the moved and the contralateral side. The histomorphometric analysis counted the number of osteoclasts, inflammatory cells, blood vessels and fibroblasts (n/104  m2 ) in periodontal ligament (PDL) of the distobuccal root. RESULTS: A reduction of 58.3% of OTM was found in Group OTM+A and 99.6% in Group OTM+Z, when compared with Group OTM. There was a significant decrease of osteoclasts and inflammatory cells in BP-treated groups. Blood vessels and fibroblastic cells decreased mainly in Group OTM+Z. CONCLUSION: Alendronate sodium and zoledronic acid have similar effects on the periodontal tissue during orthodontic treatment in rats. Especially, zoledronic acid can affect orthodontic tooth movement.