Baicalin Improves Skeletal Muscle Atrophy by Attenuating DRP-1-Mediated Mitochondrial Fission in Aged Mice

Baicalin is a natural flavonoid that has anti-apoptotic and anti-inflammatory effects. It shows some beneficial effects on muscle atrophy. However, its effects on age-related muscle atrophy are poorly understood. In this paper, we investigated whether baicalin exerts protective effect against skeletal muscle atrophy and its underlying mechanisms in aged mice using the grip strength test, histological analysis, and Western blots. Baicalin increased total muscle mass and strength in aged mice. Consistently, the cross-sectional area of quadriceps (QD) muscle significantly increased in both baicalin-administrated groups. Moreover, baicalin induced a shift in muscle fiber size distribution toward large fibers in both groups of mice. Expression levels of muscle atrophic factors, such as myostatin (MSTN) and atrogin-1, as well as pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), were elevated in aged mice, but these increases were reduced by baicalin. While mitochondrial fission regulator, dynamin-related protein 1 (DRP-1), and apoptosis-related protein (apoptotic protease activating factor 1 (Apaf-1)) expressions were higher in aged mice than young mice, and their expression were downregulated following baicalin administration. The comprehensive results of this study suggest that baicalin provides beneficial effects on the treatment of sarcopenia not only by suppressing muscle atrophic factor expression and inflammation but also attenuating DRP-1-mediated mitochondrial fission and apoptosis.