A novel model of weightlifting in mice: Signaling and gene transcription responses in skeletal muscle

Resistance exercise promotes skeletal muscle hypertrophy, prevents muscle atrophy and improves muscle function. However, despite the significant biological and clinical relevance we still have a poor understanding of the molecular and cellular mechanisms. A critical barrier is the lack of an appropriate animal model of resistance training . We have developed a novel weightlifting cage for mice to perform squat like movements against weight and subjected adult wild type mice (C57BL/6) to an acute bout of weightlifting (WL; n = 4) using sedentary mice as control (CON; n = 3). Following 3 days of acclimatization in the cage, mice in the WL group were allowed to perform weightlifting against 150% of their body weight overnight during the dark cycle (12 hrs). Immediately following the dark cycle, all the mice were sacrificed, and skeletal muscle, liver and heart tissues were harvested for RNA and protein analyses. Mice in the WL group pushed 419±83 times overnight. Semi‐quantitative RT‐PCR showed 3‐fold increase of tumor necrosis factor receptor superfamily, member 12 (Tnfrsf12a or Fn14) mRNA and 2‐fold increase of down syndrome critical region gene 1 (Dscr1) mRNA with no change in TNF‐related weak inducer of apoptosis (Tweak) mRNA in gastrocnemius muscle. Western blot analysis no significant changes in 5′ AMP‐activated protein kinase (AMPK), phospho‐AMPK (p‐AMPK Thr172 ), protein kinase B (Akt), p‐AKT Ser473 and cleaved Notch1 proteins. Therefore, we have developed a novel model of resistance exercise and confirmed that weightlifting results in increased Fn14 and Dscr1 mRNA in recruited skeletal muscle. This novel weightlifting cage may be used as a model of resistant exercise for future research. Support or Funding Information China Scholarship Council Fund (201506140108)