High-fat diet and fructose drink introduced after weaning rats, induces a better human obesity model than very high-fat diet.

In the present study, we associated a high-fat diet (HF group: 45% kcal from lipids) or very high-fat (VHF group: 60% kcal from lipids) diet with a fructose drink (10% fructose) for hydration. Normal rat chow that received the control diet (content 16.3% kcal from lipid-AIN93G) and water. The treatments were introduced soon after weaning and were administered for 70 days. We aimed to compare HF and VHF groups and find which acts as a better model mimicking human obesity. Body mass gain, final body weight, adipocyte area in inguinal depots, visceral and subcutaneous adipose depots, serum triacylglycerol, and VLDL-c were all higher in the HF group, followed by the VHF group, compared to the C group. Only the HF group showed hyperinsulinemia and hyperleptinemia and higher total caloric intake, Lee index, HOMA2-IR, and total cholesterol. Serum TNF-α and IL-6 levels were lower in the HF and VHF groups than in the C group at the end for 70 days. In Summary, the HF (45%) diet administered with fructose induced a higher similarity of metabolic and hormonal alterations associated with human obesity. PRACTICAL APPLICATIONS: High intake of lipids with sugary drinks has been associated with obesity and its comorbidities. Although a diet with 45% or 60% of lipids is considered hyperlipidic, they are different in their effects on eating behavior and also probably from a metabolic point of view. Common sense is that the reduction in intake of lipids is favorable to health. Our study shows that this is not wholly true, and this information contributes to the guidelines for the treatment of obesity. In addition, the scientific literature on the subject has shown the most diverse results and also the use of experimental models with few similarities with human obesity. Our findings can contribute as a good model of obesity initiated during childhood to investigate possible using nutritional strategies, or the adoption of ergogenic nutritional resources in future studies, for example.

Higher insulin sensitivity in EDL muscle of rats fed a low-protein, high-carbohydrate diet inhibits the caspase-3 and ubiquitin-proteasome proteolytic systems but does not increase protein synthesis.

Compared with the extensor digitorum longus (EDL) muscle of control rats (C), the EDL muscle of rats fed a low-protein, high-carbohydrate diet (LPHC) showed a 36% reduction in mass. Muscle mass is determined by the balance between protein synthesis and proteolysis; thus, the aim of this work was to evaluate the components involved in these processes. Compared with the muscle from C rats, the EDL muscle from LPHC diet-fed rats showed a reduction (34%) in the in vitro basal protein synthesis and a 22% reduction in the in vitro basal proteolysis suggesting that the reduction in the mass can be associated with a change in the rate of the two processes. Soon after euthanasia, in the EDL muscles of the rats fed the LPHC diet for 15days, the activity of caspase-3 and that of components of the ubiquitin-proteasome system (atrogin-1 content and chymotrypsin-like activity) were decreased. The phosphorylation of p70(S6K) and 4E-BP1, proteins involved in protein synthesis, was also decreased. We observed an increase in the insulin-stimulated protein content of p-Akt. Thus, the higher insulin sensitivity in the EDL muscle of LPHC rats seemed to contribute to the lower proteolysis in LPHC rats. However, even with the higher insulin sensitivity, the reduction in p-E4-BP1 and p70(S6K) indicates a reduction in protein synthesis, showing that factors other than insulin can have a greater effect on the control of protein synthesis.

Acute and subchronic antihyperglycemic activities of Bowdichia virgilioides roots in non-diabetic and diabetic rats.

AIM: The present study was undertaken to evaluate the acute and subchronic antihyperglycemic effects of methanolic extract of Bowdichia virgilioides root bark of B. virgilioides in streptozotocin (STZ)-induced diabetic rats. MATERIALS AND METHODS: The extract (100, 250 or 500 mg/kg) was orally administered to male Wistar diabetic (STZ, 42 mg/kg i.v.) and non-diabetic rats into two main protocols: (i) subchronic experiments, where animals were treated for 21 days with B. virgilioides extract and the following parameters were evaluated: Body weight, fluid and food intake (determined daily), urinary glucose and urea (every 3 days) and glycemia (every 5 days). At the end of the experimental period, skeletal muscles (extensor digitorum longus [EDL] and soleus), retroperitoneal and epididymal white adipose tissues were collected and weighed; liver samples were used for the determination of the lipid and glycogen contents; (ii) acute experiments, which evaluated the alterations on fasting and post-prandial glycemia and on glucose tolerance using the oral glucose tolerance test (OGTT). RESULTS: In subchronic experiments, the treatment with B. virgilioides extract did not change any parameter evaluated in diabetic and non-diabetic animals. On fasting and post-prandial glycemia, the extract treatment did not promote changes in the glycemia values in diabetic or non-diabetic animals. In OGTT, the treatment with 500 mg/kg B. virgilioides extract reduced the hyperglycemia peak after a glucose overload, when compared with non-treated diabetic animals, resulting in a lower area under curve. CONCLUSION: The results of our work indicate that B. virgilioides root extract promotes an acute antihyperglycemic effect in STZ-diabetic rats; this effect probably occurs through an inhibition of the intestinal glucose absorption. The continuity of the research is necessary to elucidate these possibilities.

Hydroethanolic extract of the inner stem bark of Cedrela odorata has low toxicity and reduces hyperglycemia induced by an overload of sucrose and glucose.

ETHNOPHARMACOLOGICAL RELEVANCE: Cedrela odorata L. (Meliaceae) is a native plant of the Amazon region and its inner stem bark is used in the treatment of diabetes in the form of maceration in Brazilian popular medicine. Until now, there is no scientific study on this activity. The present study was aimed at evaluating the anti-hyperglycemic activity, anti-diabetic, toxicity, antioxidant and potential mechanism of action of hydroethanolic extract of the inner stem bark of Cedrela odorata. MATERIAL AND METHODS: The inner stem bark extract of Cedrela odorata was prepared by maceration in 70% ethanol for 7 days to obtain hydroethanolic extract of Cedrela odorata (HeECo). The preliminary phytochemical analysis was performed according to procedures described in the literature. Selected secondary metabolites detected were quantified by high performance liquid chromatography (HPLC). Acute toxicity of HeECo was investigated in male and female mice with oral administration of graded doses of HeECo from 10 to 5000 mg/kg. Subchronic oral toxicity study was done by oral administration of HeECo (500 mg/kg) and vehicle for 30 days to both sexes of Wistar rats. Clinical observations and toxicological related parameters were determined. Blood was collected for biochemical and hematological analyses, while histological examinations were performed on selected organs. Anti-hiperglycemic and antidiabetic effects were evaluated in streptozotocin-induced diabetic rats. In acute evaluation, the animals received pretreatment with 250 and 500 mg/kg of HeECo, before carbohydrate overload. For subchronic effect, the antidiabetic activity of HeECo was evaluated using the same doses for 21 days. At the end of the treatments, the levels of triacylglycerols, malondialdehyde, total antioxidant status, superoxide dismutase and glutathione peroxidase activities were evaluated in the plasma. RESULTS: The extract showed low acute toxicity. HeECo exhibited inhibitory activity against α-glucosidase and caused a lowering in the peak levels of blood glucose in animals that received glucose overload by 36.7% and 24.1% in the area under the glucose curve (AUC). When the overload was sucrose, HeECo reduced the blood glucose level by 44.4% without affecting AUC. Treatment with HeECo of the blood glucose of the diabetic animals for 21 days did not lead to improvement in weight gain and regularization of the blood glucose level, but reduced the triacylglycerol and malondialdehyde levels by 36.6% and 48.1%, respectively. The activity of the antioxidant enzymes, superoxide dismutase and glutathione peroxidase were significantly increased when compared to diabetic control rats. HPLC analysis showed the presence of polyphenols, such as gallic acid, (-)- gallocatechin and (+)- catechin, the latter is present in higher quantity. CONCLUSIONS: Collectively, these data showed that HeECo could blunt the postprandial glycemic surge in rats; possibly through inhibition of alpha-glucosidase and positive modulation of antioxidant enzymes. Our findings confirmed the anti-hiperglycemic activity of HeECo in STZ- diabetic rats. Cedrela odorata is effective in diminishing glucose levels in vitro and in vivo and in ameliorating oxidative damage that occurs in diabetes and/or due to hyperglycemia in rats. According to our results, the efficacy of Cedrela odorata preparation could be due to the presence of active principles with different mode of actions at the molecular level, including α-glycosidases and glucose transporter inhibitors and antioxidant property.

A low-protein, high-carbohydrate diet increases de novo fatty acid synthesis from glycerol and glycerokinase content in the liver of growing rats.

We had previously shown that adipose tissue increased in rats fed a low-protein, high-carbohydrate (LPHC) diet (6% protein, 74% carbohydrate) without a simultaneous increase in the de novo fatty acids (FA) synthesis. In addition, impairment in insulin signaling in adipose tissues was observed in these rats. For this study, we hypothesized that the insulin signaling pathway is preserved in the livers from these rats, which contributes to an increase in liver lipogenesis and, consequently, an increase in the weight of the adipose tissue. We also hypothesized that glycerol from triacylglycerol is an important substrate for FA synthesis. Our results showed that administration of the LPHC diet induced an increase in the in vivo rate of total FA synthesis (150%) as well as FA synthesis from glucose (270%) in the liver. There were also increased rates of [U-¹4C]glycerol incorporation into glyceride-FA (15-fold), accompanied by increased glycerokinase content (30%) compared with livers of rats fed the control diet. The LPHC diet did not change the glycerol-3-phosphate generation from either glucose or glyceroneogenesis. There was an increase in the insulin sensitivity in liver from LPHC-fed rats, as evidenced by increases in IR(ß) (35%) levels and serine/threonine protein kinase (AKT) levels (75%), and basal (95%) and insulin-stimulated AKT phosphorylation (105%) levels. The LPHC diet also induced an increase in the liver sterol regulatory element-binding protein-1c content (50%). In summary, these data confirmed the hypothesis that lipogenesis and insulin signaling are increased in the livers of LPHC-fed rats and that glycerol is important not only for FA esterification but also for FA synthesis.