Pulsed ultrasound prevents lipopolysaccharide-induced muscle atrophy through inhibiting p38 MAPK phosphorylation in C2C12 myotubes

Abstract

Objective: Inflammation contributes to skeletal muscle atrophy via protein degradation induced by p38 mitogen-activated protein kinase (MAPK) phosphorylation. Meanwhile, pulsed ultrasound irradiation provides the mechanical stimulation to the target tissue, and has been reported to show anti-inflammatory effects. This study investigated the preventive effects of pulsed ultrasound irradiation on muscle atrophy induced by lipopolysaccharide (LPS) in C2C12 myotubes.

Methods: C2C12 myotubes were used in this research. The pulsed ultrasound (a frequency of 3 MHz, duty cycle of 20%, intensity of 0.5 W/cm²) was irradiated to myotube before LPS administration.

Results: The LPS increased phosphorylation of p38 MAPK and decreased the myofibril and myosin heavy chain protein (P < 0.05), followed by atrophy in C2C12 myotubes. The pulsed ultrasound irradiation attenuated p38 MAPK phosphorylation and myotube atrophy induced by LPS (P < 0.05).

Conclusions: Pulsed ultrasound irradiation has the preventive effects on inflammation-induced muscle atrophy through inhibiting phosphorylation of p38 MAPK.

Keywords: C2C12 myotubes; Lipopolysaccharide; Muscle atrophy; Pulsed ultrasound irradiation; p38 MAPK.