Remedial effects of tilapia skin peptides against dexamethasone-induced muscle atrophy in mice by modulation of AKT/FOXO3a and Sirt1/PGC-1α signaling pathways

Tilapia skin peptides (TSP) possess a range of physiological activities. This study aimed to explore the effects of TSP on Dexamethasone (DEX)-induced muscle atrophy. In vitro, C2C12 myotube myotube diameter and expression levels of the muscle-specific E3 ubiquitin ligases F -box only protein 32 (Atrogin-1) and muscle ring finger protein 1 (MuRF1) challenged with DEX were reversed by TSP. In vivo, DEX was injected subcutaneously to build muscle atrophy model mice. TSP enhanced grip strength, running distance, body lean muscle content, cross-sectional area of the gastrocnemius and tibialis anterior muscles of DEX-induced mice. Moreover, TSP inhibited the expression levels of Atrogin-1 and MuRF1. Mechanically, TSP improved DEX-induced muscle atrophy by regulating the Protein Kinase B alpha (AKT)/Forkhead box O3 protein (FOXO3a), Sirtuin 1 (Sirt1)/ peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha) signaling pathway, and downstream factors such as nuclear respiratory factor (NRF)1/2 and mitochondrial transcription factor A (TFAM).