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| Author(s): |
Fernanda Gonçalves Basso
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2013-05-27 |
| Examining board members: |
Carlos Alberto de Souza Costa;
Luis Carlos Spolidorio;
Élcio Marcantonio Junior;
Maria Elvira Pizzigatti Corrêa;
Ricardo Della Coletta
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| Advisor: | Carlos Alberto de Souza Costa |
| Abstract | |
Recent studies have demonstrated that the etiopathogenesis of bisphosphonates-induced osteonecrosis may be related, at least in part, to the cytotoxicity of these drugs on bone and oral mucosa cells. Systemic and topic antibiotic administration as well as surgical procedures have been used to treat osteonecrosis. Additionally, many clinical studies have proposed low-level laser therapy (LLLT) as an adjuvante treatment for this pathological condition. However, the effects of LLLT on bisphosphonate-treated cells have not been elucidated. Therefore, this study aimed to evaluate the effect of a potent nitrogen-containing bisphosphonate - Zoledronic Acid (ZA) - on cultured bone, fibroblast and epithelial cells, as well as to assess the effects of LLLT applied on these cells previously exposed to ZA. Three human cell lines were used: epitelial cells (HaCaT), gingival fibroblastos (HGF) and osteoblasts (SaOs-2). Cells were seeded in culture medium (DMEM) containing 10% of fetal bovine sérum (FBS) for 48 hours. After that, the culture medium was replaced by FBS-free DMEM, followed by addition of ZA at 5 ?M, for additional 48 hours. After this period, a new DMEM was added (10% FBS). The cells were subjected to LLLT using a laser diode prototype LaserTABLE (InGaAsP - 780 nm +-3 nm, 25 mW), at 0.5; 1.5; 3; 5 and 7 J/cm2. Cells were irradiated for 3 times, every 24 hours. Twentyfour hours after the last irradiation, cell viability, total protein production, alcaline phophatase activity, mineral nodule formation, gene expression of collagen type I (Col-I), fibroblastic growth factor type 2 (FGF2), vascular endotelial growth factor (VEGF) and alcaline phosphatase (ALP), and also cell morphology (SEM) were evaluated. Data were subjected to normality evaluation and statisticaly analyzed using Kruskal-Wallis and Mann-Whitney tests at 5% of significance level. ZA caused a significant decrease on cell viability, total protein production, gene expression of Col-I and VEGF for all cell lines (p<0.05), as well as intense cell morphological changes. Gene expression and activity and mineral nodule formation by osteoblasts were also negatively affected by ZA (p<0.05). LLLT promoted diverse effects, according to cell type. Considering cell lines in an isolated way, 5 and 7 J/cm2; 3 J/cm2; and 0.5 J/cm2 promoted the best results for epitelial cells, gingival fibroblastos and osteoblasts, respectively. Regarding the LLLT applied to epitelial cells pre-treated with ZA, 5 J/cm2 promoted the most significant effects. For gingival fibroblasts and osteoblasts, the most relevant results were obtained at 3 J/cm2 and 0.5 J/cm2, respectively. These data show that LLLT can promote biostimulation on bone ZA-treated cells as well as on fibroblasts and epithelial adjacent cells, what could improve local tissue repair (AU) | |