Basic nutritional investigationModulation of cytokines, resistin, and distribution of adipose tissue in C57BL/6 mice by different high-fat diets

ObjectiveTo investigate whether changing the lipid source induces metabolic changes and/or modulates the adipose tissue distribution in mice fed with a high-fat (HF) diet.MethodsC57BL/6 mice were subjected to a 10-wk control diet (10% fat) or an HF diet (60% fat) containing lard (HF-L), olive oil (HF-O), sunflower oil, or canola oil. Food intake and body weight were measured. At euthanasia, blood was collected and adipose tissue was dissected. Serum hormones and cytokines were determined.ResultsThe plasma insulin levels were higher in the HF-L and HF-O groups than in the other three groups (P < 0.0001). The levels of resistin were highest in the HF-L and HF-O groups (P < 0.0001). Leptin expression was also highest in these two groups (P < 0.0001). Of the four groups, interleukin-6 was expressed at the highest level in the HF-L group (P < 0.0005), whereas adiponectin was expressed at the lowest level (P < 0.0001). The accumulation of subcutaneous and visceral adipose tissues was higher in the HF-L group compared with the other groups. This group was hypertrophic because of excess subcutaneous fat and epididymal fat in the adipocytes. However, the ratio of subcutaneous to visceral fat was significantly lower in the HF-L and HF-O groups compared with the other groups.ConclusionIn mice fed fat-rich diets, the level of adipokines, the distribution of adipose tissue, and the metabolism of carbohydrates are more significantly influenced by the lipid content rather than the absolute amount of lipid.