Exercise training effects on inflammatory gene expression in white adipose tissue of young mice

Abstract

We aimed to determine the effects of 6 wks of exercise on inflammatory markers in mice concomitantly fed either high-fat (HF) or normal chow (NC) diets in young mice. C57BL/6 mice were randomized into (n = 10/group) an NC/sedentary (NC/SED), NC/exercise (NC/EX), HF/SED, and HF/EX groups. Treadmill exercise was performed 5 d/wk at 12 m/min, with 12% grade for 40 min/d. Liver triglycerides and gene expression of F4/80, MCP-1, TNF-α, leptin, and VEGF in visceral white adipose were determined. NC groups had lower body weights after 6 wks versus the HF groups (22.8 ± 0.2 versus 25.7 ± 0.4 g) (P < 0.0001). F4/80 gene expression (indicator of macrophage infiltration) and liver triglycerides were greatest amongst the HF/SED group, with no differences between the remaining groups. VEGF (indicator of angiogenesis) was greatest in the HF/EX versus the other 3 groups (P < 0.05). Exposure of an HF diet in sedentary young mice increased visceral adipose depots and liver triglycerides versus an NC diet. Exercise training while on the HF diet protected against hepatic steatosis and possibly macrophage infiltration within white adipose tissue. This suggests that moderate exercise while on an HF diet can offer some level of protection early on in the development of obesity.

Figure 1

Weekly body weights over the course of 6 wks while mice were exercise trained (EX) or sedentary (SED) and on either normal chow or high-fat diets (NC, HF). Closed circles: NC/SED; open Circles: NC/EX; closed Squares: HF/SED; open Squares: HF/EX. *Diet effect only (P < 0.05). High-fat (45%) feeding resulted in overall greater body weights versus NC groups. Data are mean ± SEM. n = 10/grp.

Figure 2

Liver triglycerides concentrations among the 4 experimental groups. High fat/sedentary (HF/SED) had the greatest triglyceride content compared to the 3 remaining groups (*P < 0.0001) (low fat/SED, LF/exercise (LF/EX), and HF/EX), with no differences among these three groups.

Figure 3

Leptin (a), monocyte chemoattractant protein-1 (MCP-1) (b), tumor necrosis-α (TNF-α) (c), F4/80 (d), and vascular endothelial growth factor (VEGF) (e) gene expression represented as fold change over the normal chow/sedentary (NC/SED) group. *High fat/sedentary (HF/SED) had greater F4/80 gene expression versus remaining 3 groups (P < 0.05). **HF/exercise (EX) expressed greater VEGF versus the other groups (P < 0.05). Data normalized to GAPDH, with no differences in GAPDH between groups. n = 8-9/grp.