Codonopsis lanceolata and its active component Tangshenoside I ameliorate skeletal muscle atrophy via regulating the PI3K/Akt and SIRT1/PGC-1α pathways

Skeletal muscle atrophy is caused by aging, disuse, malnutrition, and several diseases. However, there are still no effective drugs or treatments for muscle atrophy. Codonopsis lanceolata (CL), a traditional medicinal plant and food, has been reported to have anti-oxidative, anti-inflammatory, anti-tumor, and anti-obesity effects.This study aimed to investigate the efficacy and active component of CL on muscle atrophy in vitro and to confirm the effect of CL and its active component on muscle atrophy and the underlying molecular mechanisms in vivo.design/Methods This study used the dexamethasone (Dex)-induced muscle atrophy C2C12 myotube model and immobilization (IM)-induced muscle atrophy C57BL/6 mice model. In vitro study, the myotube diameter was measured. In vivo study, the grip strength, muscle mass (quadriceps, gastrocnemius, and soleus) and muscle fiber cross-sectional area (CSA) was measured. Western blot analysis and qRT-PCR were performed to confirm the underlying molecular mechanisms Results:In vitro study, CL and its main component, Tangshenoside I (TSI), effectively restored C2C12 myotube diameters decreased by Dex. Surprisingly, TSI was identified as the active component responsible for the overall efficacy of CL on muscle atrophy. In vivo study, CL and TSI, dose-dependently increased grip strength, mass muscle, and muscle fiber CSA reduced by IM. In the molecular mechanism studies, CL and TSI increased muscle protein synthesis via activating the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin complex 1 (mTORC1) pathway and decreased muscle protein degradation via inhibiting the muscle ring finger-1 (MuRF1) and muscle atrophy F-box protein (Atrogin-1) expressions. It also upregulated mitochondrial biogenesis via the silent information regulator 1 (SIRT1)/ peroxisome proliferator-activated receptor gamma and coactivator-1 alpha (PGC-1α) pathway.This study suggests that CL and its active component, TSI, can be potential drug candidates for the prevention and treatment of muscle atrophy.