Reversal of Obesity and Metabolic Disorders by Exercise in High-Fat Diet-Induced Obese C57BL/6 mice

Abstract

The current study was undertaken to examine whether 13 weeks of moderate aerobic exercise performed in the fed-state could reverse metabolic disorders associated with obesity in a C57BL/6 female mice fed diets high in saturated or unsaturated fats. Thirty one, five-weeks-old C57BL/6 female mice were allocated into three groups: normal fat diet group (NFD-Control) (10% Kcal fat), high saturated fat diet group (HSFD) (45% Kcal fat), and high unsaturated fat diet group (HUSFD) (45% Kcal fat). Mice were kept on such diets for 13 weeks. Exercise regimen was then undertaken. Mice given high fat diets were subdivided into two subgroups; sedentary or exercise for 13 weeks. Mice in the control group continued on the same diet without exercise treatment. Serum levels of glucose and lipid profile as well as plasma levels of glucagon-like peptide-1 (GLP-1) were analyzed after 13 weeks of diet induction, and at the end of the study. Intraperitoneal glucose tolerance tests were carried out after 12 weeks of the diet induction, and at THE 25TH week of the study. Findings of the present study indicated that hyperglycemia (P<0.001), hypercholesterolemia (P<0.01), and hypertriglyceridemia (P<0.05) were clearly observed in mice fed either HSFD or HUSFD for 13 weeks compared to that in NFD group, whereas serum levels of GLP-1 in both groups were significantly reduced (P<0.001). Mice in HFD groups gained significantly more in body weight than that in NFD group and became glucose intolerant (P<0.001). Exercise treatment for 13 weeks decreased hypertriglyceridemia (P<0.01) and hyperglycemia (P<0.001) observed in sedentary groups, and significantly reduced body mass index (BMI) (P<0.001) and feed efficiency (P<0.05), while significantly increased plasma levels of GLP-1 and improved glucose intolerance (19,155±305 and 16,852.5±725 mg/ dL. 120 min; respectively, P<0.01) in both HSFD- and HUSFD-fed mice. Exercise had no effect (P>0.05) on serum levels of total cholesterol (TC) and high density lipoprotein (HDL) in mice fed HFD. Exercise reverses obesity and metabolic disorders that results from long-term feeding of HFD without the need for dietary modification; these beneficial effects of exercise might be mediated by a significant increase in plasma GLP-1 levels following weight loss. This study therefore supports that exercise is an effective treatment for obesity.