MicroRNAs (miRNAs) are short, non-coding RNAs involved in the regulation of several processes associated with inflammatory diseases and infection. Bacterial infection modulates miRNA expression to subvert innate immune response. In this study, we analyzed bacterial modulation of miRNAs in bone-marrow-derived macrophages (BMMs), in which activity was induced by infection with Porphyromonas gingivalis (Pg) through a microarray analysis. Several miRNA expressions levels were modulated 3 hours post infection (at a multiplicity of infection (MOI) of 25). A bioinformatics analysis was performed to further identify pathways related to the innate immune host-response pathways that are under the influence of the selected miRNAs. To assess the effects of the identified miRNAs on cytokines secretion (pro inflammatory TNF-α and anti-inflammatory IL-10), BMMs were transfected with selected miRNAs mimics or inhibitors. Transfection with mmu-miR-155 and mmu-miR- 2137 did not modify TNF-α secretion while their inhibitors increased it. Inhibitors of mmumiR-2137 and mmu-miR-7674 increased the secretion of the anti-inflammatory IL-10. In Pginfected BMMs, mmu-miR-155-5p significantly decreased TNF-α secretion while inhibitor of mmu-miR-2137 increased IL-10 secretion. In vivo, in a Pg-induced calvarial bone resorption mouse model, injection of mmu-miR-155-5p or anti-mmu-miR-2137 reduced the size of the lesion significantly. Furthermore, anti-mmu-miR-2137 significantly reduced inflammatorycell infiltration, osteoclast activity and bone loss. Bioinformatics analysis demonstrated that pathways related to cytokines and chemokines related pathways but also osteoclast differentiation may be involved in the observed effects. The study highlights the potential therapeutic merits of targeting mmu-miR-155-5p and mmu-miR-2137 to control inflammation induced by Pg infection. To assess the regenerative process in the same animal model, we aimed to compare the effect of Bone Morphogenic Protien 2 (BMP2), Platelets Rich Plasma (PRP), Leukocyte-Platelets Rich Fibrin (L-PRF), and Polygucosamine (PGIcNAc) on bone formation in critical size bone defects in mice. One-hundred-thirty-eight mice were divided into 23 groups (n=6), negative control, different combinations of the PGIcNAc with or without of BMP2, Collagen Sponge (SurgiFoam), PRP, and L-PRF. The 5mm defect, then, was allowed to heal. After six weeks, samples were analyzed for bone formation utilizing radiographs, H&E staining, alkaline phosphatase staining. Our results show that BMP2 were able to produce 90-95% healing of critical size defects after six weeks histologically and radiographically. However, SurgiFoam, PRP and L-PRF with or without PGIcNAc were able to close 60% of the original defect. This study supports that BMP2 is more effective for bone regeneration than SurgiFoam, PRP, L-PRF and PGIcNAc.

Orientador: Joni Augusto Cirelli / Banca: Luís Carlos Spolidorio / Banca: Álvaro Francisco Bosco / Banca: Marcio Fernando de Moraes Grisi / Banca: Elton Gonçalves Zenóbio / Resumo: O objetivo do presente estudo foi avaliar histomorfometricamente o efeito do plasma rico em plaquetas (PRP), associado a enxerto ósseo autógeno e a membrana absorvível (Resolut®), no tratamento de lesões de furca grau III. Foram criados defeitos cirúrgicos nos 3os pré-molares inferiores (P3) de cinco cães, de ambos os lados, totalizando 10 dentes. Após um período de três meses de cronificação, as lesões foram divididas aleatoriamente em dois grupos de tratamento. (1) Grupo teste: PRP + enxerto ósseo autógeno + membrana; (2) Grupo controle: enxerto ósseo autógeno + membrana. Após um período de cicatrização de 90 dias, os animais foram sacrificados. A análise histológica, a partir da marcação, mostrou formação de novo cemento celular, mínima quantidade de novo osso e ligamento periodontal, em ambos os grupos. Nenhuma diferença estatisticamente significante foi observada entre os grupos teste e controle. A associação do PRP ao enxerto ósseo autógeno e membrana, ou somente, do enxerto ósseo autógeno e membrana, não apresentou vantagens estatisticamente significantes no tratamento das lesões, resultando em preenchimento parcial das furcas e regeneração periodontal limitada à marca experimental das lesões. / Abstract: The objective of this study was to evaluate histomorphometrically the platelet-rich plasma (PRP) effects, associated with autogenous bone graft and absorbable membrane (Resolut®), for the treatment of Class III furcation defects, in 5 dogs. Surgical defects were created in the 3nd mandibular premolars (P3) on both sides, of each dog, totaling 10 teeth. After a period of three months of chronified, the defects were randomly divided in two treatment groups. (1) Group Tests: PRP + graft bone autogenous + membrane; (2) Group Control: graft bone autogenous + membrane. Animals were sacrificed after 90 days healing. Histologic evaluation revealed new cellular cementum, low amount of bone and periodontal ligament formation in both groups, starting from the demarcation. No statistically significant difference was observed between Groups Test and Control. PRP + autogenous bone graft + membrane or autogenous bone graft + membrane no present statistically significant advantages on the lesions treatment, resulting in furcation partial filling and periodontal regeneration limited to the experimental mark of the lesions. / Doutor

Made available in DSpace on 2014-06-11T19:33:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-08-26Bitstream added on 2014-06-13T20:05:24Z : No. of bitstreams: 1 fernandes_jma_dr_arafo.pdf: 1627813 bytes, checksum: c33f2da49d4d220b69231200c1a3f0c1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo do presente estudo foi avaliar histomorfometricamente o efeito do plasma rico em plaquetas (PRP), associado a enxerto ósseo autógeno e a membrana absorvível (Resolut®), no tratamento de lesões de furca grau III. Foram criados defeitos cirúrgicos nos 3os pré-molares inferiores (P3) de cinco cães, de ambos os lados, totalizando 10 dentes. Após um período de três meses de cronificação, as lesões foram divididas aleatoriamente em dois grupos de tratamento. (1) Grupo teste: PRP + enxerto ósseo autógeno + membrana; (2) Grupo controle: enxerto ósseo autógeno + membrana. Após um período de cicatrização de 90 dias, os animais foram sacrificados. A análise histológica, a partir da marcação, mostrou formação de novo cemento celular, mínima quantidade de novo osso e ligamento periodontal, em ambos os grupos. Nenhuma diferença estatisticamente significante foi observada entre os grupos teste e controle. A associação do PRP ao enxerto ósseo autógeno e membrana, ou somente, do enxerto ósseo autógeno e membrana, não apresentou vantagens estatisticamente significantes no tratamento das lesões, resultando em preenchimento parcial das furcas e regeneração periodontal limitada à marca experimental das lesões. / The objective of this study was to evaluate histomorphometrically the platelet-rich plasma (PRP) effects, associated with autogenous bone graft and absorbable membrane (Resolut®), for the treatment of Class III furcation defects, in 5 dogs. Surgical defects were created in the 3nd mandibular premolars (P3) on both sides, of each dog, totaling 10 teeth. After a period of three months of chronified, the defects were randomly divided in two treatment groups. (1) Group Tests: PRP + graft bone autogenous + membrane; (2) Group Control: graft bone autogenous + membrane. Animals were sacrificed after 90 days healing. Histologic evaluation revealed new cellular cementum, low amount of bone and periodontal ligament formation in both groups, starting from the demarcation. No statistically significant difference was observed between Groups Test and Control. PRP + autogenous bone graft + membrane or autogenous bone graft + membrane no present statistically significant advantages on the lesions treatment, resulting in furcation partial filling and periodontal regeneration limited to the experimental mark of the lesions.