A post-mitotic in vitro murine as a model of muscle damage and repair

Sarcopenia is a degenerative condition characterized by the atrophy and functional decline of myofibers, resulting in disability. While the clinical risk factors are known, there is no validated in vitro model to understand the molecular mechanisms and identify therapeutics. To tackle this challenge, we generated an in vitro post-mitotic muscular system by differentiating mouse myoblast cells, namely C2C12. After 12 days of differentiation, cells were expressing physiological markers of myotubes and became self-contracting. Importantly, transcriptomic analyses demonstrated high similarity (r=0.70) when compared to primary human myotubes (HSkMC) providing evidence of resemblance to human cells. Next, we starved and incubated cells with dexamethasone and observed myotube shrinkage, oxidative stress, modification of anabolic, inflammatory, and catabolic markers recapitulating sarcopenia. Conversely, cell refeeding resulted in a recovery in the model with nutrient deprivation but not when incubated also with dexamethasone. In conclusion, we present a model of sarcopenia due to nutrient deprivation and corticosteroids. This model may allow more efficient and effective future research to identify therapeutics against sarcopenia in humans.