Mung bean protein hydrolysate ameliorates dexamethasone-induced skeletal muscle atrophy by modulating muscle protein turnover and oxidative stress in rat

Skeletal muscle atrophy is characterized by a progressive decline in muscle mass, resulting in decreased muscle strength and impaired physiological function. Mung bean has been considered a rich source of plant-based protein that contains high quantities of amino acids. Thus, this study aimed to investigate the underlying mechanisms of mung bean hydrolysates through both in vitro and in vivo experiments related to muscle atrophy caused by dexamethasone (DEX). In vitro study was conducted to determine the potential benefits of mung bean on myotubes. C2C12 cells were treated with graded concentrations of mung bean hydrolysates for 24 h and 48 h. Cell viability, proliferation, membrane toxicity, LDH activity, ATP concentration, glucose consumption, and mRNA expressions of myostatin ( Mstn) and myosin heavy chain 1 (Myh1) were evaluated. Additionally, Sprague Dawley rats were divided into 5 groups: control, DEX, DEX with mung bean protein hydrolysates (250 or 500 mg/kg/day), and DEX with BCAA (600 mg/kg/day). After 10 days of DEX administration, body weight, muscle mass, and muscle strength were assessed, and muscle tissues were collected for further analysis. In vitro results demonstrated that mung bean hydrolysates promoted Myh1 expression and increased ATP concentration in C2C12 myotubes. Moreover, the hydrolysates significantly improved muscle strength and tension in rats treated with DEX. The insulin sensitivity improvement, which is associated with muscle glucose uptake and glycogen storage, was also observed, along with a significant increase in protein synthesis and a decrease in protein degradation markers. Furthermore, this study revealed the antioxidative effects of mung bean in atrophic muscles, as evidenced by the reduction of malondialdehyde level and the increased activity of antioxidant enzymes. These findings suggest that mung bean hydrolysates effectively enhanced myogenesis, ATP generation, and mitigated oxidative stress and muscle degradation, resulting in improved muscle functions in rats with DEX-induced muscle atrophy.