Marcela Sene-Fiorese

Efficiency of intermittent exercise on adiposity and fatty liver in rats fed with high-fat diet

Objective: This study aimed to examine and compare the effects of continuous or intermittent exercises on adiposity and fatty liver in rats fed with high‐fat diet.

Dieta hiperlipídica e capacidade secretória de insulina em ratos

OBJETIVOS: Este estudo investigou, em ratos, os efeitos da administracao cronica de uma dieta hiperlipidica palatavel sobre: ganho de peso, adiposidade, conteudos de glicogenio hepatico e muscular, glicemia e insulinemia, morfologia do pâncreas e secrecao de insulina por ilhotas isoladas, incubadas in vitro. METODOS: Ratos Wistar machos (21 dias de idade) foram alimentados com dieta hiperlipidica palatavel ou com dieta padrao, durante 15 semanas. Peso corporal e consumo de racao foram avaliados diariamente, glicose e insulina plasmatica foram avaliadas semanalmente. Apos o sacrificio, pâncreas, figado, gastrocnemio e tecidos adiposos foram coletados e pesados. Cortes do pâncreas foram analisados por microscopia otica comum. Insulina plasmatica e a secretada por ilhotas isoladas, apos incubacao na presenca de diferentes concentracoes de glicose, foram avaliadas por radioimunoensaio. RESULTADOS: A dieta hiperlipidica palatavel aumentou a adiposidade, a percentagem do ganho de peso corporal e o conteudo do glicogenio hepatico, quando comparada a dos animais alimentados com dieta padrao. Glicemias e insulinemias de jejum nao diferiram entre os grupos. A secrecao de insulina das ilhotas isoladas dos ratos aumentou, nos tratados com dieta hiperlipidica, apenas em presenca de concentracoes fisiologicas de glicose (G= 8,3mM). A dieta hiperlipidica reduziu o tamanho do pâncreas, mas aumentou o numero de celulas beta. Alem disso, o lumen dos vasos sanguineos pancreaticos apresentou-se reduzido, quando comparado aos controles. CONCLUSAO: A obesidade provocada pela dieta hiperlipidica nao alterou os niveis de glicose e insulina de jejum desses animais. Apesar das alteracoes morfologicas do pâncreas, a manutencao da normoglicemia dos ratos tratados com dieta hiperlipidica, provavelmente, deveu-se a capacidade preservada de suas ilhotas em secretar insulina.

Food restriction and refeeding induces changes in lipid pathways and fat deposition in the adipose and hepatic tissues in rats with diet-induced obesity

The aim of this study was to determine the effects of successive cycles of a moderately restrictive diet and refeeding with a high‐fat diet on the metabolism of the adipose and hepatic tissues of obese rats. Rats were assigned to the following groups: a chow diet; a high‐fat diet; a moderate caloric restriction; or a moderate caloric restriction plus refeeding. Some animals in each group were given [1‐14C]triolein intragastrically, while others received an intraperitoneal injection of 3 mCi 3H2O. All animals were killed by decapitation. The retroperitoneal, visceral epididymal and omental white adipose tissues, brown adipose tissue, liver and blood were immediately removed. The lipid uptake from the diet, in vivo rate of lipogenesis, percentage of fat, lipid profile and leptin concentration were analysed. The high‐fat diet promoted an increase in fatty liver (P≤ 0.05), adiposity mass (P≤ 0.05) and the plasma concentration of leptin (P≤ 0.05) and a decreased lipid uptake in white adipose tissue depots (P≤ 0.05) in relation to the chow diet. The moderate caloric restriction did not reverse the changes promoted by the high‐fat diet but induced a small decrease in adiposity, which was reversed after refeeding, and the animals maintained a dyslipidaemic profile and high fat deposition in the liver. We can conclude that the high‐fat diet and subsequent moderate caloric restriction plus refeeding increased the risks of developing visceral obesity, dyslipidaemia and non‐alcoholic fatty liver disease, which suggests that this type of experimental protocol can be used to study mechanisms related to the metabolic syndrome.

Effects of two different types of swimming exercise on adiposity and lipid profile in rats with exogenous obesity

Investigar os efeitos do exercicio de natacao intermitente em relacao ao exercicio continuo e ao sedentarismo,em ratos Wistar, apos o desenvolvimento de obesidade exogena pela administracao de uma dieta hiperlipidicapalatavel sobre: evolucao do peso corporal, ingestao alimentar, adiposidade, percentual de gordura dostecidos e perfil lipidico.

The potential of phototherapy to reduce body fat, insulin resistance and “metabolic inflexibility” related to obesity in women undergoing weight loss treatment

The metabolic flexibility is often impaired in diseases associated with obesity, and many studies are based on the hypothesis that dysfunction in peripheral tissues such as skeletal muscle, liver and adipose tissue represent the etiology of development of metabolic inflexibility. Experimental evidence shows that the use of phototherapy combined with exercise was effective in controlling the lipid profile, reducing the mass of adipose tissue, suggesting increased metabolic activity and changes in lipid metabolism. However, we found few data in the literature involving the use of phototherapy in association to physical training in the obese population. Thus, our objective was to evaluate the effects of exercise training (aerobic plus resistance exercises) plus phototherapy (laser, 808 nm) on metabolic profile and adiponectinemia in obese women.

Can low-level laser therapy (LLLT) associated with an aerobic plus resistance training change the cardiometabolic risk in obese women? A placebo-controlled clinical trial

INTRODUCTION Obesity is one of the most important link factors to coronary artery disease development mainly due to the pro-inflammatory and pro-thrombotic states favoring atherosclerosis progression. The LLLT acts in the cellular metabolism and it is highly effective to improve inflammation. The same occur in response to different kinds of exercise. However, we have not known the associate effects using LLLT therapies with aerobic plus resistance training as strategy specifically with target at human obesity control and its comorbidities. OBJECTIVE Investigate the effects of the LLLT associated with aerobic plus resistance training on cardiometabolic risk factors in obese women. METHODOLOGY Women aged 20-40 years (BMI ≥ 30 kg/m(2)), were divided into 2 groups: Phototherapy (PHOTO) and Placebo. They were trained aerobic plus resistance exercises (in a concurrent mode), 1h, 3 times/week during 16 weeks. Phototherapy was applied after each exercise session for 16 min, with infrared laser, wavelength 808 nm, continuous output, power 100 mW, and energy delivery 50 J. The body composition was measured with bioimpedance. Inflammatory mark concentrations were measured using a commercially available multiplex. RESULTS LLLT associated with aerobic plus resistance training was effective in decrease neck (P=0.0003) and waist circumferences (P=0.02); percentual of fat (P=0.04); visceral fat area (P=0.02); HOMA-IR (P=0.0009); Leptin (P=0.03) and ICAM (P=0.03). Also, the reduction in leptin (P=0.008) and ICAM-1 (0, 05) was much more expressive in the phototherapy group in comparison to placebo group when analyzed by delta values. CONCLUSION LLLT associated with concurrent exercise (aerobic plus resistance training) potentiates the exercise effects of decreasing the cardiometabolic risk factors in obese woman. These results suggest the LLLT associated with exercises as a new therapeutic tool in the control of obesity and its comorbidities for obese people, targeting to optimize the strategies to control the cardiometabolic risk factors in these populations.

Can low-level laser therapy when associated to exercise decrease adipocyte area?

Obesity affects approximately 20% of the world population, and exercise is the primary non-pharmacological therapy. The combined use of exercise and low-level laser therapy (LLLT) may potentiate the effects promoted by exercise. The objective of this study was to investigate the effects of exercise in combination with phototherapy on adipocyte area, activity of the enzyme citrate synthase and muscle morphological analysis. We used 64 Wistar rats, which were divided into eight groups with 8 rats each: sedentary chow-diet (SC); sedentary chow-diet plus laser therapy (SCL), exercised chow-diet (EC); exercised chow-diet plus laser therapy (ECL); sedentary high-fat diet (SH); sedentary high-fat diet plus laser therapy (SHL); exercised high-fat diet (EH); exercised high-fat diet, laser therapy (EHL). The animals were submitted to a program of swimming training for 90min/5 times per week for 8weeks and LLLT (GA-Al-AS, 830nm) at a dose of 4.7J/point and a total energy of 9.4J/animal, with duration of 47s, which was applied to both gastrocnemius muscles after exercise. We conclude that the combined use of exercise and phototherapy increases the activity of the enzyme citrate synthase and decreases the white adipocyte area epididymal, retroperitoneal and visceral in obese rats, enhancing the effects of exercise.

Effect of High Intensity Interval and Continuous Swimming Training on Body Mass Adiposity Level and Serum Parameters in High-Fat Diet Fed Rats

This study aimed to investigate the effects of interval and continuous training on the body mass gain and adiposity levels of rats fed a high-fat diet. Forty-eight male Sprague-Dawley rats were randomly divided into two groups, standard diet and high-fat diet, and received their respective diets for a period of four weeks without exercise stimuli. After this period, the animals were randomly divided into six groups (n = 8): control standard diet (CS), control high-fat diet (CH), continuous training standard diet (CTS), continuous training high-fat diet (CTH), interval training standard diet (ITS), and interval training high-fat diet (ITH). The interval and continuous training consisted of a swimming exercise performed over eight weeks. CH rats had greater body mass gain, sum of adipose tissues mass, and lower serum high density lipoprotein values than CS. The trained groups showed lower values of feed intake, caloric intake, body mass gain, and adiposity levels compared with the CH group. No significant differences were observed between the trained groups (CTS versus ITS and CTH versus ITH) on body mass gains and adiposity levels. In conclusion, both training methodologies were shown to be effective in controlling body mass gain and adiposity levels in high-fat diet fed rats.

Efeito da suplementação com ácido linoléico conjugado e do treinamento em natação sobre a composição corporal e os parâmetros bioquímicos de ratos Wistar em crescimento

OBJECTIVE: The objective of this study was to evaluate the effects of conjugated linoleic acid supplementation associated with moderate swimming training on body composition, food efficiency and consumption, blood glucose, lipid profile, and muscle and liver glycogen of Wistar rats. METHODS: Thirty-day old Wistar rats were divided into the following groups: inactive, inactive with 2% conjugated linoleic acid supplementation, active, and active with 2% conjugated linoleic acid supplementation. They remained in individual cages with food and water ad libitum, temperature of 23±1oC and a light and dark cycle of 12 hours for 8 weeks. The active groups swam for one hour three times per week. The animals were killed and the plasma, white and brown fat tissues, gastrocnemius muscle and liver were collected and weighted. RESULTS: Supplementation per se did not promote food intake or body weight changes in the animals. Fasting glucose (p<0.05) and high density lipoproteins (HDL, p<0.05) increased and triacylglycerols decreased. Supplementation associated with activity decreased body mass (p<0.05) and increased the relative weight of fat tissues, liver and fasting glucose. CONCLUSION: Conjugated linoleic acid supplementation associated with physical activity seems to influence energy balance. On the other hand, the increased liver weight indicates that intake of this fatty acid may have undesirable side-effects, increasing the chances of developing fatty liver. This new perspective makes way for new studies including histological analyses of the liver and gene expression of key enzymes from the lipid and carbohydrate metabolism, associated or not with different physical training protocols.

Experimental Diet Models in the Investigation of Obesity

Several experimental models of dietary manipulation have been created for the purpose of investigating chronic-degenerative diseases. In general, such models allow for the assessment of the qualitative and quantitative alterations of nutrients and substances contained in a food regimen. Recent studies have made use of alternative forms of dietary manipulation that have resulted in the experimental development of diseases such as diabetes, dyslipidemia, and obesity (Duarte et al. 2003; Estadella et al. 2004; Manzoni et al. 2005; Cheik 2005; Guerra 2005).