OBJECTIVE: Beyond its established glucose-lowering and weight-reducing benefits, glucagon-like peptide-1 receptor agonists (GLP-1RAs) such as liraglutide may also mitigate sarcopenia. This study investigates the effects of liraglutide on diabetic sarcopenia and its underlying mechanisms.
METHODS: A type 2 diabetic SD rat model was induced using a high-fat, high-sugar diet supplemented with a low dose of streptozotocin. Comparisons were made among control (Con), diabetic (DM), and liraglutide-treated (Li) groups for gastrocnemius muscle wet weight and length, histology (HE staining), immunofluorescence for muscle fiber typing, and Western blotting for aging-related proteins and YAP/TAZ pathway components. Concurrently, C2C12 myoblasts were differentiated into myotubes, treated with 60 mM glucose to model diabetic conditions, and assessed for morphological changes, senescence (SA-β-gal staining), and protein expression dynamics.
RESULTS: Diabetic rats displayed significant reductions in muscle mass, length, and cross-sectional area, along with disorganized fiber architecture, all of which were improved by liraglutide. In vitro, C2C12 myotubes showed accelerated aging and atrophy under high-glucose conditions, which were significantly reduced by liraglutide. Analysis revealed increased expression of aging markers P53 and P21 and decreased YAP/TAZ/TEAD and Cyclin D1 levels in diabetic conditions, which were reversed following liraglutide treatment. The inhibition of YAP significantly negated the protective effects of liraglutide.
CONCLUSION: High glucose promotes muscle cell aging and sarcopenia, processes that liraglutide can attenuate by modulating the YAP/TAZ signaling pathway. This study underscores liraglutide's potential to alleviate muscle degeneration in diabetic sarcopenia through its regulatory impact on critical aging pathways.
