Unravelling rheumatoid arthritis-related sarcopenia: animal models, pathogenesis, and anti-sarcopenia preclinical...

Rheumatoid arthritis (RA) is an essential cause of secondary sarcopenia, and patients with RA face a higher risk of developing sarcopenia. In the literature, there is a lack of reviews on animal models of RA-related sarcopenia. This review examines sarcopenia-related changes and mechanisms in induced and immune-mediated arthritis animal models and highlights potential preclinical therapies. The mechanisms for developing sarcopenia in these animal models involved inflammation, protein degradation pathways, protein synthesis, muscle regeneration and differentiation, oxidative stress, energy metabolism, and amino acid metabolism. Some anti-rheumatic drugs, supplements and nutrients, antioxidants, and physical therapy and training have been shown to improve muscle atrophy, maintain muscle mass, and prevent grip strength loss in different RA-related sarcopenia animal models. Overall, this review aims to deepen the mechanistic understanding of RA-related sarcopenia and provide a basis for developing innovative therapies.