Aquo-ethanolic extract of Lilii Bulbus attenuates dexamethasone-induced muscle loss and enhances muscle strength in experimental mice

Traditionally, Lilium lancifolium bulb is known for its ability to nourish yin, nourish the lungs, clear the heart, soothe coughs, reduce irritability, and calm the mind. In Oriental Medicine, it is categorized as a tonic remedy for alleviating symptoms of fatigue and enhancing the strength of bones and muscles.

In this study, we aimed to validate the effectiveness of the aquo-ethanolic extract of Lilli Bulbus (LBE) in a dexamethasone (DEX)-induced muscle atrophy model, both in vitro and in vivo, and elucidate its mechanism of action through muscle transcriptome analysis. The effects of LBE on the viability and myotube density of C2C12 myoblasts and differentiated C2C12 myotubes with and without DEX treatment were investigated. LBE pretreatment protected C2C12 myoblast cells and increased the muscle density of C2C12 myotubes in response to DEX. LBE showed potent free radical scavenging activities in cell-free biochemical assays as well as antioxidant activity in C2C12 myoblasts. LBE also exhibited protective effects in an experimental animal model of DEX-induced muscle atrophy, showing muscular function and motor coordination recovery. Transcriptomic analysis of three different muscle tissues from mice with DEX-induced muscle atrophy showed that the regulation of the extracellular matrix was perturbed by glucocorticoid treatment, and this perturbation was reversed by LBE treatment.

Collectively, LBE alleviated skeletal muscle loss and maintained muscle function from the chronic toxicity of DEX by protecting muscle cells from various stressful conditions, as well as DEX itself, inhibiting muscle protein degradation, and preserving the muscle tissue microenvironment.