The Effect of Cold Temperature and Exercise on BAT and Browning of WAT

Abstract

The present study aimed to investigate the effects of cold exposure and/or exercise on resting energy metabolism over 24 h and on BAT activity and browning of WAT related gene responses. Forty ICR male mice were divided into four groups: thermoneutrality-untrained (23 ± 1°C in room temperature, n=10), cold-water immersion (24 ± 1°C, n=10), exercise in neutral temperature (34 ± 1°C, n=10), and exercise in cold temperature (24 ± 1°C, n=10). The mice performed swim training (30 min to 60 min, 5 days/week) for 8 weeks. After end of experiment, we confirmed BAT activity and browning of WAT-related gene expression changes in interscapular-BAT and inguinal adipose tissue, and measured resting energy metabolism over 24 h. The results showed that the relative tissue weights of BAT and inguinal fat tissue differed by temperature (p = 0.016, p= 0.001 respectively). The UCP1 mRNA expression in BAT showed a significant effect in the exercised groups (p = 0.038). The sum of the oxygen uptake, only a significant temperature effect (p = 0.040) was observed and the average of the RER showed a significant temperature (p = 0.024) and exercise (p = 0.008) effect. Our data demonstrate that cold exposure and exercise independently induces the gene expression of thermogenic markers and the energy metabolic rate. The relative expression of these markers and the change of the energy metabolism indicators differed across the tissues and experimental treatments. In conclusion, our results suggest that cold exposure and exercise has no synergy effect on thermogenic markers of BAT and beige/brite adipose tissue and energy metabolism over 24h.