Differential effects of increasing physical activity and reducing energy intake on cardiometabolic and energetic parameters in obesity-prone juvenile rats

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Although the rise in adolescent obesity plateaued from 2003 to 2012, health implications associated with excess adiposity in the adolescent years remain problematic. As such, we utilized an obesity-prone (OP) rat model to investigate how physical activity affects whole body energetics and metabolism as well as adipose tissue-specific changes during the juvenile period. Male OP rats were obtained at 4 wks of age and randomized into one of the following three groups (n=10/group): 1) high-fat diet (HFD), sedentary (Sed), 2) HFD exercise (Ex), or 3) HFD weight-matched (WM). Animals were placed in indirect calorimetry chambers at 11 wks of age and glucose tolerance tests were conducted at 12 wks. Animals were sacrificed from 16- 18 wks of age. BW gain was significantly attenuated with WM equal to the Ex group for the duration of the study (Sed 569[plus or minus]12.89g, Ex 467[plus or minus]19.80g, WM 476[plus or minus]3.38g; p less than 0.05). Dark cycle spontaneous physical activity (SPA) was significantly increased in the Ex group in comparison to Sed and WM groups. Using the Matsuda index (MI), Ex significantly improved insulin sensitivity compared to the WM and Sed group (Sed: 2.18[plus or minus]0.33MI, Ex: 5.13[plus or minus]0.02MI, WM: 2.25[plus or minus]0.27MI, p less than 0.05). Both Ex and WM groups experienced reductions in pro-inflammatory markers with concomitant increases in anti-inflammatory genes across multiple adipose tissue depots. We found that the two interventions were almost equivocal in terms of improvements in body composition and reducing adipose tissue inflammation. We also found that voluntary exercise increased SPA while, both interventions increased total energy expenditure