E-01 Featured Science Session - Exercise and Dysregulated Immune and Inflammatory Responses: FRIDAY, MAY 29, 2009 8:00 AM - 10:00 AM ROOM: 607
We have previously demonstrated that modification with diet and exercise improved inflammation in adipose tissue in sedentary adult mice after being placed on a high fat diet. Given that adolescent obesity is on the rise, there is little to no data available on inflammation in adipose and the effect exercise would have in such a population.
PURPOSE: To determine the effects of a 6 wk intervention of exercise or no exercise with either a high fat (HF) diet or normal chow (NC) diet in juvenile mice.
METHODS: At 5 wks of age, C57BL/6 mice were divided into 4 groups (n=10/grp): NC/sedentary (NC/SED), NC/exercise (NC/EX), HF/sedentary (HF/SED), and HF/exercise (HF/EX). The HF diet was 45 % fat, 35 % carbohydrate and 20 % protein. Treadmill exercise was performed 5 d/wk at 13 m/min, 10% grade for 40 min/d. Mice were placed on the 6 wk diet and exercise intervention concomitantly. Body weights were measured weekly and the liver, epidydmal and peri-renal fat pads were weighed at sacrifice. Liver triglycerides were measured and quantitative RT-PCR was performed using F480 to assess inflammation.
RESULTS: After 1 wk of intervention, the NC groups had lower body weights than the HF groups (19.8 ± 0.3 vs. 21.4 ± 0.3 g) (p<.01). This pattern remained at 6 wks (22.8 ± 0.2 vs. 25.7 ± 0.4 g) (p<0.0001). Fat pad weights were highest among the HF diet groups (p<0.0001), with the HF/SED having the greatest epidydmal and peri-renal fat pads and the HF/EX having the next largest fat pad weights. No differences were observed between the two NC groups. F480 gene expression, an indicator of macrophage infiltration and inflammation, and liver triglycerides were greatest amongst the HF/SED group, with no differences between the remaining 3 groups. CONCLUSIONS: Exposure to a HF diet in sedentary juvenile mice increased visceral adipose depots and liver triglycerides versus a NC diet. Interestingly, exercise training while on the HF diet appeared to "protect" the liver and inflammation within adipose. These data suggest that promoting physical activity in adolescents is paramount for reducing obesity-related health complications.