Metabolic syndrome signs in Wistar rats submitted to different high-fructose ingestion protocols

Abstract

In search of an adequate model for the human metabolic syndrome, the metabolic characteristics of Wistar rats were analysed after being submitted to different protocols of high fructose ingestion. First, two adult rat groups (aged 90 d) were studied: a control group (C1; n 6) received regular rodent chow (Labina, Purina) and a fructose group (F1; n 6) was fed on regular rodent chow. Fructose was administered as a 10 % solution in drinking water. Second, two adult rat groups (aged 90 d) were evaluated: a control group (C2; n 6) was fed on a balanced diet (AIN-93G) and a fructose group (F2; n 6) was fed on a purified 60 % fructose diet. Finally, two young rat groups (aged 28 d) were analysed: a control group (C3; n 6) was fed on the AIN-93G diet and a fructose group (F3; n 6) was fed on a 60 % fructose diet. After 4-8 weeks, the animals were evaluated. Glucose tolerance, peripheral insulin sensitivity, blood lipid profile and body fat were analysed. In the fructose groups F2 and F3 glucose tolerance and insulin sensitivity were lower, while triacylglycerolaemia was higher than the respective controls C2 and C3 (P,0·05). Blood total cholesterol, HDL and LDL as well as body fat showed change only in the second protocol. In conclusion, high fructose intake is more effective at producing the signs of the metabolic syndrome in adult than in young Wistar rats. Additionally, diet seems to be a more effective way of fructose administration than drinking water.Fructose: Metabolic syndrome: Insulin sensitivity: Body fat Clinically, the metabolic syndrome involves a cluster of disturbances in which glucose intolerance represents an important symptom. Metabolic syndrome diagnosis implies in positive results to at least three metabolic alterations including insulin resistance, hypertension, obesity, endothelial dysfunction and blood lipid profile alterations (1,2) . These multiple risk factors accelerate the incidence of CVD in a cooperative way (1 -4) . Obesity prevalence has quadrupled in the past 25 years in the USA; 16 % of children and 30 % of adults are now affected and many of these obese individuals suffer from the metabolic syndrome (5)

High dietary fructose load aggravates lipid metabolism in the liver of Wistar rats through imbalance between lipogenesis and fatty acid oxidation

“…In the present study, 60% fructose consumption was found to be associated with hypertriglyceridemia. On the other hand, we did not observe excessive triglyceride accumulation in the liver, which is in accordance with the results of other animal studies using a 60% fructose diet (Kelley et al, 2004;de Moura et al, 2009). According to these results, we presume that the hepatic overproduction of triglyceride-rich lipoproteins due to a liquid highfructose diet is channeled into secretory pathways instead of being accumulated in the liver, resulting in excessive visceral adiposity (Sam et al, 2009) and an increased risk of metabolic complications (Lemieux et al, 2007).…”

Fructose and NAFLD: metabolic implications and models of induction in rats

“…In adult animals there was an increase of fat liver, white adipose tissue, total cholesterol, HDL, LDL, triglycerides and serum insulin. Also offering 60% fructose in the diet was more effective than offering 10% fructose in water 32 .…”

“…On the other hand, some studies have reported the use of such diets for periods of up to 40 weeks. When offered for a short time, about five weeks, it constitutes a model to analyze the forms of treatment of MS, since it is possible to observe some of its constituents, such as dyslipidemia and increased body fat 32 .…”

Influence of Gut Microbiota on Inflammation and Pathogenesis of Sugar Rich Diet Induced Diabetes

“…Diet-induced diabetes is largely caused by disorders of fat metabolism, resulting in an excess deposition of fat in various tissues. Diet is considered to be one of the important environmental factors influencing the composition of the gut microbiota within a host and affecting their functional relationships [21,22]. Impaired glucose tolerance testing is an important diagnostic indicator for type 2 diabetes [12].…”

“…Fructose and sucrose consumption by young rats has been revealed to induce lower glucose tolerance and reduced insulin sensitivity as well as increased TG, cholesterol, and body fat [22]. The elevated TG levels are commonly associated with a cluster of metabolic risk factors known as the metabolic syndrome [23].…”