Formula diet is effective for the reduction and differentiation of visceral adipose tissue in Zucker fatty rats

Abstract

Aim: Formula diet (FD), which is used as a tool for calorie restriction, has beneficial effects on metabolic disorders in obese patients; however, the molecular mechanism is not fully understood. Methods: Sixteen-week-old male Zucker Diabetic Fatty (ZDF) rats were divided into 3 groups (n = 10 each): calorie-controlled low-fat diet [Control; 75 kcal/day, protein: fat: carbohydrate (P:F:C)= 25:15: 60], calorie-restricted low-fat diet (CR-LFD; 56 kcal/day, P:F:C = 25:15:60), and calorie-restricted FD (CR-FD; 56 kcal/day, P:F:C = 50:14:36) group, and fed each diet for 4 weeks. Before the study, baseline data were obtained in 10 rats. After 4 weeks, body weight and epididymal fat weight were measured, and blood samples, mesenteric and subcutaneous adipose tissues were collected for analyses. Messenger RNA expression was evaluated by real-time PCR, and protein expression by Western blotting. Results: The decrease in epididymal fat weight was significantly greater in the CR-FD group than in control and CR-LFD groups, although changes in body weight were not different among groups. The decrease in fasting plasma glucose and increase in plasma adiponectin were greater in the CRFD group than in the control group, but not in the CR-LFD group. The decrease in triglyceride and increase in HDL-cholesterol were greatest in the CR-FD group. Both mRNA and protein of peroxisome proliferator-activated receptor γ coactivator (PGC)-1α, adiponectin, lipoprotein lipase and PPARγ were overexpressed in the CR-FD group, especially in mesenteric adipose tissue. Conclusions: FD may have beneficial effects on abdominal obesity and metabolic disorders by reducing visceral fat and improving glucose and lipid profiles, possibly through modulating adipose tissue function.