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Doctoral Thesis
DOI
Document
Author
Full name
Gabriela Pereira de Souza
Institute/School/College
Knowledge Area
Date of Defense
Published
Bauru, 2018
Supervisor
Committee
Santos, Carlos Ferreira dos (President)
Akashi, Ana Eliza
Cardoso, Sandra Lia do Amaral
Ponce, Daniela
Title in Portuguese
Avaliação dos efeitos do losartan na doença periodontal induzida experimentalmente em ratos
Keywords in Portuguese
Doença periodontal
Losartan
Receptor AT1
Abstract in Portuguese
A doença periodontal (DP) compreende um grupo de lesões que afeta os tecidos periodontais de proteção e de suporte e pode acarretar na perda dentária. Interações entre patógenos microbianos e vários sistemas desempenham um papel crítico no desenvolvimento e progressão da DP via liberação de vários mediadores inflamatórios e imunológicos. Experimentos recentes de nosso grupo de pesquisa mostraram que existe a expressão de RNAm para todos os componentes do Sistema Renina-Angiotensina (SRA), presença da renina e atividade da Enzima Conversora de Angiotensina (ECA) em tecido gengival de ratos e que o losartan inibe a perda óssea no modelo de DP induzida experimentalmente em ratos. Portanto, o presente trabalho propõe-se a investigar os mecanismos pelos quais o losartan (antagonista do receptor AT1) possui efeitos anti-inflamatórios no modelo da DP induzida experimentalmente em ratos. Para tanto, foi utilizado o modelo de indução da DP por colocação de ligadura ao redor do primeiro molar inferior de ratos divididos em treze grupos com 15 animais cada, que foram tratados com losartan (50 mg/kg/dia) via gavage. As técnicas utilizadas neste trabalho foram: indução da DP em ratos, a análise tomográfica da perda óssea alveolar (MicroCT), análise 2D com uso de software específico (ImageJ), RT-PCR e análise histológica do tecido periodontal. Após a coleta, os dados foram devidamente analisados por meio de gráficos e tabelas, sendo utilizado ANOVA, seguida de um pós-teste para determinar a significância da diferença entre os grupos dentro de um mesmo ensaio. Foi adotado nível de significância de 5%. O losartan foi capaz de atuar no aumento da expressão de enzimas, citocinas, quimiocinas e receptores, tais como: AT2, MAS, AT1a, AT1b, AGT, OPG, ALP, PHEX, RUNX2, BGLAP, IL-18, IL-21 e MMPs. Além disso, promoveu a diminuição de citocinas pró-inflamatórias como IL-6, IL-10 e INF, indicando assim seu papel anti-inflamatório, dados observados na análise molecular do tecido gengival e ósseo. Macroscopicamente foi confirmado que o tratamento com losartan foi capaz de atenuar a perda óssea. Os achados histológicos corroboram com as análises de MicroCT e RT-PCR. Concluiu-se então que o losartan possui efeito protetor na preservação do periodonto em animais submetidos à DP devido à diminuição de moléculas envolvidas na inflamação.
Title in English
Assessment of the effects of losartan on experimentally induced periodontal disease in rats
Keywords in English
Losartan
Periodontal disease
Receiver AT1
Abstract in English
Periodontal disease (PD) comprises a group of lesions that affect the periodontal tissues of protection and support and can lead to tooth loss. Interactions between microbial pathogens and various systems play a critical role in the development and progression of PD through release of various inflammatory and immunological mediators. Recent experiments from our research group have shown that mRNA expression exists for all components of the Renin-Angiotensin System (RAS), presence of renin and Angiotensin Converting Enzyme (ACE) activity in rat gingival tissue and that losartan inhibits the bone loss in the experimentally induced PD model in rats. Therefore, the present work aims to investigate the mechanisms by which losartan (AT1 receptor antagonist) has anti-inflammatory effects in the PD model induced experimentally in rats. For this, the PD induction model was used by placing ligation around the lower first molar of rats divided into thirteen groups with 15 animals each, which were treated with losartan (50mg / kg / day) via gavage. The techniques used in this work were: induction of PD in rats, tomographic analysis of alveolar bone loss (MicroCT), 2D analysis using specific software (ImageJ), RT-PCR and histological analysis of periodontal tissue. After the data collection, the data were analyzed by means of graphs and tables, using ANOVA, followed by a post-test to determine the significance of the difference between groups within the same trial. A significance level of 5% was adopted. Losartan was able to increase the expression of enzymes, cytokines, chemokines and receptors, such as AT2, MAS, AT1a, AT1b, AGT, OPG, ALP, PHEX, RUNX2, BGLAP, IL-18, IL-21 and MMPs. In addition, it promoted the reduction of proinflammatory cytokines such as IL-6, IL-10 and INF, thus indicating its anti-inflammatory role, data observed in the molecular analysis of gingival and bone tissue. Macroscopically it was confirmed that treatment with losartan was able to attenuate bone loss. Histological findings corroborate with MicroCT and RT-PCR analyzes. It was concluded that losartan has a protective effect on the preservation of the periodontium in animals submitted to PD due to the decrease of the molecules involved in the inflammation.
 
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Publishing Date
2019-09-10
 
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