Fish oil consumption prevents glucose intolerance and hypercorticosteronemy in footshock-stressed rats

<p>Abstract</p> <p>Background</p> <p>Environmental stress plays an important role in the development of glucose intolerance influencing lipid and glucose metabolism through sympathetic nervous system, cytokines and hormones such as glucocorticoids, catecholamines and glucagon. Otherwise, fish oil prevents glucose intolerance and insulin resistance. Although the mechanisms involved are not fully understood, it is known that sympathetic and HPA responses are blunted and catecholamines and glucocorticoids concentrations can be modulated by fish consumption. The aim of the present study was to evaluate whether fish oil, on a normal lipidic diet: 1) could prevent the effect of footshock-stress on the development of glucose intolerance; 2) modified adiponectin receptor and serum concentration; and 3) also modified TNF-α, IL-6 and interleukin-10 (IL-10) levels in adipose tissue and liver. The study was performed in thirty day-old male Wistar randomly assigned into four groups: no stressed (C) and stressed (CS) rats fed with control diet, and no stressed (F) and stressed (FS) rats fed with a fish oil rich diet. The stress was performed as a three daily footshock stress sessions.</p> <p>Results</p> <p>Body weight, carcass fat and protein content were not different among groups. FS presented a reduction on the relative weight of RET. Basal serum glucose levels were higher in CS and FS but 15 min after glucose load just CS remained with higher levels than other groups. Serum corticosterone concentration was increased in CS, this effect was inhibited in FS. However, 15 min after footshock-stress, corticosterone levels were similar among groups. IL-6 was increased in EPI of CS but fish oil consumption prevented IL-6 increase in FS. Similar levels of TNF-α and IL-10 in RET, EPI, and liver were observed among groups. Adipo R1 protein concentration was not different among groups. Footshock-stress did not modify AdipoR2 concentration, but fish oil diet increases AdipoR2 protein concentration.</p> <p>Conclusions</p> <p>Footshock-stress promotes glucose intolerance associated to corticosterone serum level and epididymal white adipose tissue IL-6 concentration increase. The fish oil consumption by stressed rats normalized the stress responses. These results suggested that fish oil intake could be useful to minimize or prevent the development of diseases associated to the stress.</p

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.Methods and Procedures: Wistar rats were divided according to diet composition-chow diet (C) or high-fat diet (H)-and kinds of exercise-sedentary (S), continuous (CE), or intermittent (IE) exercises. The CE group swam 90 min/day, and the IE group swam 3 x 30 min/day (at 4-h intervals between sessions); both groups exercised 5 days/week during 8 weeks. Body weight and food intake were recorded daily. Lipogenesis rate in vivo was determined by the incorporation of (H2O)-H-3 into saponified lipids in retroperitoneal (RET), epididymal (EPI), and visceral (VIS) white adipose tissues, brown adipose tissue (BAT), liver (L), and gastrocnemius muscle (GAST) using the gravimetric method. Total cholesterol, high-density lipoprotein (HDL)-cholesterol, and triacylglycerol (TG) were analyzed.Results: The major finding of this study is that IE was more efficient than CE in reducing the adverse effects of high-fat diet and sedentarism. There was an improvement in the lipid profile and a reduction in food intake, body weight gain, visceral and central adiposity, and fatty liver, contributing to the control of obesity and other comorbidities, including nonalcoholic fat liver diseases.Discussion: Earlier studies have discussed the effects of diet consumption on adiposity and their relation to chronic diseases and obesity. This study discusses the effects of high-fat diet consumption and the different kinds of exercise on weight gain, adiposity, fatty liver, and lipid profile in rats. The results may depend on the exercise, time of each session, age, gender, and experimental period.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES