Efeito antiobesogênico do óleo de peixe: função do tecido adiposo marrom e branco

• Autor(a) principal: Bargut, Thereza Cristina Lonzetti
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/7785
• topic: Obesity; Brown adipose tissue; Thermogenesis; White adipose tissue; Fish oil; N-3 polyunsaturated fatty acids; Obesidade; Tecido adiposo marrom; Termogênese; Tecido adiposo branco; Óleo de peixe; Ácidos graxos poli-insaturados n-3; Obesidade; Óleo de peixe; Tecido adiposo marrom; Ácidos graxos insaturados; CNPQ::CIENCIAS BIOLOGICAS::MORFOLOGIA

Brown adipose tissue (BAT) and white adipose tissue (WAT) modulation is associated with prevention or reduction of body mass gain. Fish oil has several beneficial effects which can be related to these tissues. Thus, we aimed to evaluate the anti-obesity effects of different high-fat diets with fish oil on BAT thermogenesis and WAT lipogenesis and beta-oxidation. For this, we used 3-mo-old C57BL/6 male mice that were divided into four groups: one that received a standard-chow diet (SC, 10% kcal of lipids) and three that received a high-fat diet (HF, 50% kcal of lipids). We obtained the HF with lard group (HF-L), the HF with lard plus fish oil group (HF-L+FO), and the HF with fish oil group (HF-FO). Diets were administrated for eight weeks, and food intake was evaluated daily and the body mass, weekly. At the end of the experiment, we performed indirect calorimetry and an oral glucose tolerance test. At sacrifice, glycemia was assessed, the blood was punctured to obtain plasma and interscapular BAT and epididymal WAT were dissected and stored. Plasmatic leptin, triglycerides and insulin were analyzed. Adiposity index and HOMA-IR were calculated. BAT and WAT were evaluated through confocal and light microscopy. RT-qPCR and Western blot were performed for analyses of thermogenic markers, fatty acids and glucose uptake and oxidation, and PPAR in BAT, and lipogenesis, beta-oxidation and PPAR in WAT. In relation to the results, the HF-L group presented elevated body mass gain and adiposity, associated with adipocyte hypertrophy, hyperleptinemia, hypertriglyceridemia, glucose intolerance and insulin resistance, displaying a condition that simulates obesity and metabolic syndrome. On the contrary, fish oil intake in both groups (HF-L+FO and HF-FO) was able to reduce body mass gain and adiposity, without affecting food intake. It also increased energy expenditure, normalized plasmatic leptin and triglycerides as well as glucose tolerance and insulin resistance. These effects were associated with increases in thermogenic markers, in uptake and oxidation of fatty acids and glucose and in PPAR expression in BAT. In WAT, lipogenesis was reduced and beta-oxidation and PPAR expression were increased. In conclusion, our results demonstrated that fish oil intake has anti-obesity effects in mice through beneficial modulation of BAT and WAT and can, therefore, represent an auxiliary alternative therapy against obesity and its comorbidities.