The effects of exercise and cold exposure on mitochondrial biogenesis in skeletal muscle and white adipose tissue.
Level 5 - mechanism / opinion, no new human data
Animal research (controlled rodent experiment).
PubMed 28715885 · doi:10.20463/jenb.2017.0020
What was done
Forty 5-week-old male ICR mice were divided into four groups (n = 10 each): thermoneutral untrained control (23 ± 1 °C room temperature), cold-water immersion (24 ± 1 °C), swimming exercise in neutral temperature water (34 ± 1 °C), and swimming exercise in cold water (24 ± 1 °C). Mice performed swimming (30 to 60 min, 5 times weekly) for 8 weeks. Gene expression of PGC-1α, NRF1, and Tfam was measured in soleus muscle and inguinal adipose tissue, and protein expression was measured in soleus muscle.
What was found
In soleus muscle, PGC-1α mRNA expression increased with cold exposure (p = 0.006) and exercise (p = 0.05), with a significant interaction (p = 0.005). NRF1 mRNA increased with exercise (p = 0.001), but not cold exposure (p = 0.1222) or interaction (p = 0.875). Tfam mRNA showed no exercise effect. Soleus PGC-1α protein levels responded to temperature (p = 0.045), but not exercise (p = 0.397) or interaction (p = 0.292). Soleus Tfam protein increased with exercise (p = 0.012), while NRF1 protein showed no significant changes. In inguinal adipose tissue, PGC-1α mRNA showed no significant changes; NRF1 mRNA changed with exercise (p = 0.01), cold (p = 0.011), and interaction (p = 0.000); Tfam mRNA changed with exercise (p = 0.000) and interaction (p = 0.001). Numerical means, fold changes, and variances were not reported in the abstract.
Why it matters
This study provides mechanistic rodent data showing that cold exposure and exercise induce tissue-specific, interactive transcriptional and translational responses related to mitochondrial biogenesis in skeletal muscle and white adipose tissue.
Limits
Findings from young male mice cannot be directly translated to human metabolism or females. The abstract lacks numerical effect sizes, dispersion metrics, adipose tissue protein quantification, and functional measures of mitochondrial respiration.
Cited by
- supports Cold exposure elevates norepinephrine, which increases PGC-1alpha and mitochondrial content in skeletal muscle tissue.