The Anti-Muscle Atrophy Effects of Ishige sinicola in LPS-Induced C2C12 Myotubes through Its Antioxidant and Anti-Inflammatory Actions

Inflammation and oxidative stress are known to be major factors in muscle atrophy. The objective of this study was to evaluate whether the antioxidant activity of Ishige sinicola ethanol extract (ISE) and fractions from ISE could prevent lipopolysaccharide (LPS)-induced muscle atrophy in C2C12 myotubes. IS was extracted with ethanol and fractionated with five organic solvents. Then, ISE and five fractions from ISE were used to evaluate the total antioxidant activity and the protective effect of LPS-induced muscle atrophy in C2C12 myotubes. The ISE and butanol (BuOH) fraction showed higher total antioxidant activity and higher total phenol content than other fractions of ISE. The ISE and BuOH fraction significantly attenuated the LPS-induced diameter of C2C12 myotubes as well as the mRNA and protein expression levels of the muscle-specific E3 ubiquitin ligases. The mRNA expression of forkhead box O type 3α was stimulated by LPS, which was suppressed by the BuOH fraction but not ISE. Furthermore, ISE and the BuOH fraction significantly reduced LPS-stimulated gene expression of pro-inflammatory cytokines and inflammation-inducible enzymes, which was mediated by through the inhibition of the p38/extracellular signal-regulated kinase signaling pathway. Thus, ISE exerts a protective effect against muscle atrophy in LPS-induced C2C12 myotubes through the antioxidant activity and anti-inflammatory effects of ISE.