Fernanda Oliveira Duarte

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.

The effects of exercise modalities on adiposity in obese rats

OBJECTIVE: The aim of the present study was to evaluate the effect of both swimming and resistance training on tumor necrosis factor-alpha and interleukin-10 expression, adipocyte area and lipid profiles in rats fed a high-fat diet. METHODS: The study was conducted over an eight-week period on Wistar adult rats, who were divided into six groups as follows (n = 10 per group): sedentary chow diet, sedentary high-fat diet, swimming plus chow diet, swimming plus high-fat diet, resistance training plus chow diet, and resistance training plus high-fat diet. Rats in the resistance training groups climbed a vertical ladder with weights on their tails once every three days. The swimming groups swam for 60 minutes/day, five days/week. RESULTS: The high-fat diet groups had higher body weights, a greater amount of adipose tissue, and higher tumor necrosis factor-alpha expression in the visceral adipose tissue. Furthermore, the high-fat diet promoted a negative change in the lipid profile. In the resistance training high-fat group, the tumor necrosis factor-alpha expression was lower than that in the swimming high-fat and sedentary high-fat groups. Moreover, smaller visceral and retroperitoneal adipocyte areas were found in the resistance training high-fat group than in the sedentary high-fat group. In the swimming high-fat group, the tumor necrosis factor-alpha expression was lower and the epididymal and retroperitoneal adipocyte areas were smaller compared with the sedentary high-fat group. CONCLUSION: The results showed that both exercise modalities improved the lipid profile, adiposity and obesity-associated inflammation in rats, suggesting their use as an alternative to control the deleterious effects of a high-fat diet in humans.

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.

Resistance training suppresses intra-abdominal fatty acid synthesis in ovariectomized rats.

Ovarian hormone loss is associated with a shift in fat distribution to intra-abdomin al adipose tissue (intra-AAT) depots and with lipid metabolism disorders, which predisposes individuals to developing insulin resistance. Resistance training (RT) prevents increases in intra-AAT after ovarian hormone loss. However, the molecular mechanisms underlying these changes remain unclear. We investigated the effects of ovariectomy and RT on gene expression related to lipogenesis and fat oxidation in the intra-AAT of ovariectomized rats. Sprague-Dawley rats (n=6/group) were divided into the groups: sham-sedentary, ovariectomized-sedentary, sham-RT and ovariectomized-RT. RT groups performed a 10-week climbing program on a ladder with progressive overload. Intra-AAT was subjected to morphometric and mRNA analysis. Ovariectomized-sedentary group had larger adipocytes and higher expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), sterol regulatory element-binding protein-1c (SREBP-1c), stearoyl-CoA desaturase-1 (SCD-1), acetyl-CoA carboxylase (ACC), hormone-sensitive lipase (HSL) and lower expression of the oxidative carnitinepalmitoyltransferase-I (CPT-1). RT counteracted OVX-induced increases in PPAR-γ and SCD-1 and decreased SREBP-1c. ACC and HSL were downregulated in ovariectomized-RT compared with the ovariectomized-sedentary group. Ovariectomized-RT group had the highest CPT-1 gene expression. Adipocyte size decreased in ovariectomized-RT group. Results suggest that RT reduces intra-AAT adipocyte size in ovariectomized rats by suppressing intra-AAT fatty acid synthesis and enhancing fatty acid β-oxidation.

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.

Physical training improves visceral adipose tissue health by remodelling extracellular matrix in rats with estrogen absence: a gene expression analysis

Adipose tissue development is associated with modifications involving extracellular matrix remodelling, and metalloproteinases play a significant role in this process. Reduced circulating sexual hormones cause impacts on the size, morphology and functions of the adipose tissue, increasing susceptibility to diseases. This study investigated whether exercise training may be an alternative strategy to combat the effects promoted by estrogen decay through modulation in gene expression patterns in the extracellular matrix (ECM) of visceral adipose tissue of ovariectomized rats. Nulliparous rats (n = 40) were randomly distributed into four groups (n = 10/group): sham sedentary (Sh‐S), sham resistance training (Sh‐Rt), ovariectomized sedentary (Ovx‐S) and ovariectomized resistance training (Ovx‐Rt). The Sh‐S animals did not have any type of training. The body mass and food intake, ECM gene expression, gelatinase MMP‐2 activity and adipocyte area were measured. A lack of estrogen promoted an increase in body mass, food intake and the visceral, parametrial and subcutaneous adipocyte areas. The ovariectomy upregulated the expression of MMP‐2, MMP‐9, TGF‐β, CTGF, VEGF‐A and MMP‐2 activity. On the other hand, resistance training decreased the body mass, food intake and the adipocyte area of the three fat depots analysed; upregulated TIMP‐1, VEGF‐A and MMP‐2 gene expression; downregulated MMP‐9, TGF‐β and CTGF gene expression; and decreased the MMP‐2 activity. We speculate that resistance training on a vertical ladder could play an important role in maintaining and remodelling ECM by modulation in the ECM gene expression and MMP‐2 activity, avoiding its destabilization which is impaired by the lack of estrogen.

Experimental type 2 diabetes induction reduces serum vaspin, but not serum omentin, in Wistar rats

Vaspin and omentin are adipose tissue adipokines that have often been related to obesity and its comorbidities. The aim of this study was to investigate the behaviour of serum omentin and vaspin in models of type 2 diabetes. To do this, Wistar rats (~200 g) were randomly divided into two groups: a non‐diabetic group (n = 6) and a diabetic group fed on a high‐fat diet (n = 6) and a low dose of streptozotocin (Sigma®). All procedures were approved by the Brazilian Ethics Committee. Body weight (BW) and food intake were recorded daily. Tail blood glucose levels were assessed at the end of the diabetes induction period. The insulin tolerance test (ITT) was performed after the diabetes induction period (7 weeks). The serum and tissues (liver, pancreas, and retroperitoneal (RET), epididymal (EPI) and visceral (VIS) white adipose tissues) were immediately removed and weighed. Analyses of levels of insulin, omentin, vaspin, adiponectin and inflammatory cytokines IL‐6, IL‐8 (CXCL8), TNF‐α and C‐reactive protein (CRP) in serum were performed using the enzyme‐linked immunosorbent assay (ELISA). Our results showed that IL‐8 and CRP serum levels in the diabetic group were significantly higher than in the non‐diabetic group. Vaspin and adiponectin values were lower for the diabetic group than for the non‐diabetic group. Omentin, IL‐6 and TNF‐α values did not differ between the groups. Our results showed that both the metabolism of the adipose tissue and the secretion of adipokines may be affected in diabetic rats. Omentin showed no difference between the groups, although the vaspin values decreased in the diabetic group.