Exercise and spirulina control non-alcoholic hepatic steatosis and lipid profile in diabetic Wistar rats

<p>Abstract</p> <p>Background</p> <p>Diabetes mellitus is associated with metabolic dysfunctions, including alterations in circulating lipid levels and fat tissue accumulation, which causes, among other pathologies, non-alcoholic fatty liver disease (NAFLD).</p> <p>Aim of the study</p> <p>The objective of this study was to analyse the effects of physical exercise and <it>spirulina </it>intake on the control of NAFLD in diabetic Wistar rats.</p> <p>Methods</p> <p>Diabetes was induced in the animals through intravenous administration of alloxan. The rats were divided into four groups: Diabetic Control (DC) - diabetic rats fed with a control diet and no physical exercise; Diabetic <it>Spirulina </it>(DS) - diabetic rats fed with a diet that included <it>spirulina</it>; Diabetic <it>Spirulina </it>and Exercise (DSE) - diabetic rats fed with a diet that included <it>Spirulina </it>and that exercised; and Diabetic Exercise (DE) - diabetic rats fed with a control diet and that exercised.</p> <p>Results</p> <p>The groups DS, DSE, and DE presented lower plasma concentrations of LDL cholesterol than DC, as well as lower levels of total liver lipids in groups DS, DSE, and DE in comparison to DC.</p> <p>Conclusion</p> <p>Thus, <it>spirulina </it>appears to be effective in reducing total circulating levels of LDL-cholesterol and hepatic lipids, alone or in conjunction with physical exercise in diabetic rats.</p

Dietary restriction, caloric value and the accumulation of hepatic fat

<p>Abstract</p> <p>Background</p> <p>Studies using laboratory animals under what are considered to be "standard" conditions normally offer unrestricted amounts of food to the animals, which can lead to metabolic disorders. Moreover, standard diets have different compositions.</p> <p>Aim</p> <p>Therefore, the aim of the present study was to assess the effects of two non-isocaloric diets (commercial Purina^®and AIN-93M), which are considered standard diets, on the accumulation of fat in the liver of rats when offered ad libitum or in a restricted amount.</p> <p>Methods</p> <p>Thus, 40 Wistar rats (90 days old) were separated into 4 groups according to the amount of food offered (ad libitum or dietary restriction) and the type of diet (commercial diet, 3,028.0 kcal/g or AIN-93M, 3,802.7 kcal/g): animals fed the commercial Purina^®diet ad libitum (AP), animals fed restricted amounts of the commercial Purina^®diet (RP), animals fed the AIN-93M diet ad libitum (AD), and animals fed restricted amounts of the AIN-93M diet (RD). Dietary restriction consisted of pair-feeding the RP and RD groups with 60% of the total food consumed by the corresponding ad libitum groups.</p> <p>Results</p> <p>Because of its higher carbohydrate and calorie content, AIN-93M was found to accelerate weight gain, reduce glucose tolerance and peripheral insulin sensitivity, and increase the amount of fat in the liver when compared to the commercial diet. Conversely, a 40% dietary restriction assisted in weight loss without causing malnutrition, contributing to an improved glucose tolerance and higher levels of HDL cholesterol.</p> <p>Conclusion</p> <p>Therefore, differences in the amount of carbohydrates and calories provided by the diet can lead to important metabolic disorders, such as impaired tolerance and accumulation of hepatic fat, and dietary restriction improves serum and tissue lipid profiles in laboratory animals.</p

Exercise training in the aerobic/anaerobic metabolic transition prevents glucose intolerance in alloxan-treated rats

<p>Abstract</p> <p>Background</p> <p>Ninety percent of cases of diabetes are of the slowly evolving non-insulin-dependent type, or Type 2 diabetes. Lack of exercise is regarded as one of the main causes of this disorder. In this study we analyzed the effects of physical exercise on glucose homeostasis in adult rats with type 2 diabetes induced by a neonatal injection of alloxan.</p> <p>Methods</p> <p>Female Wistar rats aged 6 days were injected with either 250 mg/kg of body weight of alloxan or citrate buffer 0.01 M (controls). After weaning, half of the animals in each group were subjected to physical training adjusted to meet the aerobic-anaerobic metabolic transition by swimming 1 h/day for 5 days a week with weight overloads. The necessary overload used was set and periodically readjusted for each rat through effort tests based on the maximal lactate steady state procedure. When aged 28, 60, 90, and 120 days, the rats underwent glucose tolerance tests (GTT) and their peripheral insulin sensitivity was evaluated using the HOMA index.</p> <p>Results</p> <p>The area under the serum glucose curve obtained through GTT was always higher in alloxan-treated animals than in controls. A decrease in this area was observed in trained alloxan-treated rats at 90 and 120 days old compared with non-trained animals. At 90 days old the trained controls showed lower HOMA indices than the non-trained controls.</p> <p>Conclusion</p> <p>Neonatal administration of alloxan induced a persistent glucose intolerance in all injected rats, which was successfully counteracted by physical training in the aerobic/anaerobic metabolic transition.</p