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Doctoral Thesis
DOI
https://doi.org/10.11606/T.5.2019.tde-04062019-121709
Document
Author
Full name
Anna Laura Viacava Américo
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2019
Supervisor
Committee
Evangelista, Fabiana de Sant'Anna (President)
Casarini, Dulce Elena
Lima, Fabio Bessa
Brum, Patricia Chakur
Title in Portuguese
Prevenção da obesidade e da resistência à insulina através do treinamento físico aeróbio: papel do sistema renina angiotensina no tecido adiposo branco
Keywords in Portuguese
Browning
Exercício
Obesidade
Resistência à insulina
Sistema renina angiotensina
Tecido adiposo branco
Abstract in Portuguese
A obesidade é fator de risco para o desenvolvimento de resistência à insulina (RI), diabetes tipo 2 (DM2) e doenças cardiovasculares, e o treinamento físico aeróbio (TFA) é recomendado para a prevenção e o tratamento de tais doenças. O sistema renina angiotensina (SRA), especificamente as alças ECA/Ang II/AT1 e ECA2/Ang (1-7)/Mas, está envolvido no desenvolvimento e progressão da obesidade e da RI, e por isso é considerado um potencial alvo terapêutico. O objetivo do estudo foi investigar se a prevenção da obesidade e da RI está associada com a modulação das alças do SRA no tecido adiposo branco (TAB). Para isso, camundongos machos adultos C57BL6/J foram separados em grupos (n=10/grupo) sedentários (SED) alimentados com dieta normocalórica (NO) e de cafeteria (CAF) (SED-NO e SED-CAF) e treinados (TF) alimentados com dieta NO e CAF (TF-NO e TF-CAF). O TFA foi realizado simultaneamente com as dietas durante 8 semanas. Os resultados revelaram que o grupo SED-CAF apresentou maior peso corporal e adiposidade, intolerância à glicose e RI, enquanto o TFA preveniu tais prejuízos no grupo TF-CAF. No TAB periepididimal (TAB-PE), os grupos SED-CAF e TF-CAF reduziram a expressão de p-AKT, aumentaram a expressão de ATGL, p-HSL e IL-6. Embora a ECA2 sérica tenha aumentado nos grupos TF-NO e TF-CAF, e a Ang (1-7) sérica aumentado no grupo TFNO, não houve modificação nos componentes de ambas as alças do SRA no TAB-PE. No TAB subcutâneo (TAB-SC), o TFA reduziu a razão p-AKT/t-AKT e aumentou a expressão da ATGL nos grupos TF-NO e TF-CAF e, aumentou a t-HSL e razão p-HSL/t-HSL no TF-CAF. O TFA preveniu a hipertrofia dos adipócitos no TF-CAF e aumentou a expressão da UCP-1 apenas no TF-NO. O grupo TF-CAF aumentou a expressão dos receptores AT1, AT2 e Mas, enquanto o TF-NO aumentou a Ang (1-7) e a razão Ang (1-7)/Ang II no TAB-SC. Foi observada correlação positiva entre a UCP-1 e a constante de decaimento de glicose (Kitt) e, entre a UCP-1 e a Ang (1-7). O TFA preveniu a obesidade e a RI em animais submetidos à dieta de cafeteria, e a contribuição do TAB-PE e do TAB-SC foi por meio da redução na expressão de proteínas envolvidas na sinalização da insulina e do aumento na expressão de proteínas sinalizadoras de lipólise. Além disso, o TFA não impediu o aumento de marcador inflamatório no TAB-PE, porém preveniu o prejuízo na expressão de genes termogênicos no TAB-SC induzido pela dieta de cafeteria. A inalteração ou a modulação parcial de componentes das alças ECA/Ang II/AT1 e ECA2/Ang(1-7)/Mas no TAB-PE sugere que o SRA não participou dos efeitos induzidos pelo TFA associados à prevenção de obesidade e RI. No entanto, no TAB-SC, o aumento na concentração de Ang (1-7) no grupo dieta normocalórica e dos receptores Mas e AT2 no grupo dieta cafeteria induzido pelo TFA, sugerem a contribuição do SRA na prevenção de obesidade e RI
Title in English
Prevention of obesity and insulin resistance through aerobic physical training: role of the renin angiotensin system in white adipose tissue
Keywords in English
Adipose tissue white
Browning
Exercise
Insulin resistance
Obesity
Renin angiotensin system
Abstract in English
Obesity is a risk factor for the development of insulin resistance (IR), type 2 diabetes (T2D) and cardiovascular disease, and aerobic exercise training (AET) is recommended for the prevention and treatment of such diseases. The renin angiotensin system (RAS), specifically the ACE/Ang II/AT1 and ACE2/Ang (1-7)/Mas, is involved in the development and progression of obesity and IR, and is therefore considered a potential therapeutic target. The aim of the study was to investigate whether the prevention of obesity and IR is associated with the modulation of the RAS axis in white adipose tissue (WAT). For this, adult male C57BL6/J mice were divided into groups (n= 10/group) sedentary (SED) fed normocaloric diet (NO) and cafeteria diet (CAF) (SED-NO and SED-CAF) and trained (TF) fed NO and CAF diet (TF-NO and TF-CAF). The AET was performed simultaneously with the diets for 8 weeks. The results showed that the SEDCAF group presented higher body weight and adiposity, glucose intolerance and IR, while AET prevented such damages in the TF-CAF group. In the periepididimal WAT (WAT-PE), the SED-CAF and TF-CAF groups reduced the expression of p-AKT, increased the expression of ATGL, p-HSL and IL-6. Although serum ACE2 increased in the TF-NO and TF-CAF groups, and Ang (1-7) increased in the TF-NO group, there was no change in the components of both RAS axis in WAT-PE. In the subcutaneous WAT (WAT-SC), AET reduced the p-AKT/t-AKT ratio and increased ATGL expression in TFNO and TF-CAF groups and increased t-HSL and p-HSL/t-HSL ratio in TF-CAF. AET prevented adipocyte hypertrophy in TF-CAF and increased UCP-1 expression only in TF-NO. The TF-CAF group increased the expression of AT1, AT2 and Mas receptors, whereas TF-NO increased Ang (1-7) and Ang (1-7)/Ang II ratio in WAT-SC. Positive correlation was observed between UCP-1 and the glucose decay constant (Kitt) and between UCP-1 and Ang (1-7). In conclusion, AET prevented obesity and IR in animals submitted to the cafeteria diet, and the contribution of WAT-PE and WAT-SC was reducing the expression of proteins involved in insulin signaling and increasing the expression of signaling proteins of lipolysis. In addition, AET did not prevent the increase of inflammatory marker in the WAT-PE, but prevented the loss in the expression of thermogenic genes in the WAT-SC induced by the cafeteria diet. The unalteration or partial modulation of components of the ACE/Ang II/AT1 and ACE2/Ang (1-7)/Mas axis in WAT-PE suggests that RAS did not participate in the AET-induced effects associated with prevention of obesity and IR. However, in the WAT-SC, the Ang (1-7) concentration increase in the normocaloric diet group and the Mas and AT2 receptors increase in the cafeteria diet group induced by AET suggest the association of RAS with the prevention of obesity and IR
 
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Publishing Date
2019-06-04
 
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