Age-dependent effect of high-fructose and high-fat diets on lipid metabolism and lipid accumulation in liver and kidney of rats

Abstract

BackgroundThe metabolic syndrome (MS) is characterized by variable coexistence of metabolic and pathophysiological alterations which are important risk factors for developing of type II diabetes and/or cardiovascular diseases. Increased of MS patients in worldwide has stimulated the development of experimental models. However, it is still challenging to find an dietetic model that most closely approximates human MS and, in addition, is not yet fully established the effect of different diets of MS in lipid metabolism in rats of different ages. The aim of this study was to evaluate the effect of different diets of MS in lipid metabolism and ectopic fat deposition and define the most appropriate diet for inducing the characteristic disturbances of the human MS in rats of different ages.MethodsYoung (4 weeks old) and adult rats (12 weeks old) were given a high-fat (FAT) or high-fructose diet (FRU) for 13 weeks and biochemical, physiological, histological and biometric parameters were evaluated.ResultsIn young rats, the FAT diet induced increased mean blood pressure (MAP) and heart rate (HR), body weight after 6 to 10 weeks, and in the 13th week, increased the liver, mesenteric, retroperitoneal and epididymal fat weights, fasting glucose, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and reduced HDL cholesterol; and also induced non-alcoholic fatty liver disease (NAFLD) and renal inflammatory infiltrates. In adult rats, the FRU diet induced transient elevations of MAP and HR in the 6th week, and, at 13 weeks, increased fasting glucose, triglycerides, total cholesterol, AST and ALT; increased liver, kidneys and retroperitoneal fat weights; and induced macrovesicular and microvesicular NAFLD, the presence of fat cells in the kidney, glomerular sclerosis, and liver and kidney inflammation. Additionally, the FAT and FRU diets induced, respectively, increases in liver glycogen in adults and young rats.ConclusionsOur data show that FRU diet in adult rats causes biggest change on metabolism of serum lipids and lipid accumulation in liver and kidney, while the FAT diet in young rats induces elevation of MAP and HR and higher increased visceral lipid stores, constituting the best nutritional interventions to induce MS in rats.

Experimental models of metabolic syndrome in rats

“…Many of the experimental models of MS are also associated with changes in liver that are similar to hepatic steatosis. Such findings have been reported as a result of feeding animals with fat-enriched diet (8,13), or with diet combining fat and carbohydrates (12,28), as well as fructose-treated rats (7,22). In our experiment liver TG were elevated significantly in the HFHF group compared to the control one.…”

“…In some cases these lipid parameters are elevated -e.g. in diets rich in fructose (12), or in diets rich in fat and fructose (21,23). In others, no changes are reported in analogous experimental settings (20).…”

“…De Castro et al (12) found decrease of HDLcholesterol only in young rats (age of 4 weeks), but not in older animals (age of 12 weeks). Our results are in agreement with these data in respect to older rats, since our animals are in the same age range.…”

“…Lard or beef fat are usually used. The mixed models utilizing both animal fats rich in saturated fatty acids and fructose are considered most relevant to the MS in men (10,11,12,13).…”

Beneficial Effect of Bis(Hinokitiolato)Zn Complex on High-fat Diet-induced Lipid Accumulation in Mouse Liver and Kidney

“…Renal alterations such as lipid accumulation lead to increased organ weight and inflammatory infiltrates. The increased release of proinflammatory cytokines may be associated with kidney damage and oxidative stress (33)(34)(35). Moreover, numerous studies of renal function in DM and diabetic nephropathy evaluated the size of the glomerulus to determine the glomerular hypertrophy or collagen IV deposition as a measure of matrix deposition (36).…”