• Journal of Microbiology and Biotechnology
• /
• 제33권7호
• /
• pp.915-925
• /
• 2023

Sarcopenia is defined as loss of muscle mass and strength due to aging. Recent studies show that sarcopenia may improve via the gut-muscle axis, suggesting that gut health may affect muscle phenotypes. In this study, we aimed to investigate the ability of Lactobacillus rhamnosus JY02 as a probiotic strain isolated from kimchi to alleviate sarcopenia. L. rhamnosus JY02-conditioned medium (CM) reduced dexamethasone (DEX)-induced myotube diameter atrophy and expression of muscle degradation markers (MuRF1 and atrogin-1) in C2C12 cells. The amelioration of sarcopenia was investigated by measuring body composition (lean mass), hand grip strength, myofibril size (using histological analysis), and mRNA and protein expression of muscle-related factors in a DEX-induced mouse model. The results of these analyses showed that L. rhamnosus JY02 supplementation promoted the production of muscle-enhancement markers (MHC Iβ, MHC IIα, and Myo-D) and reduced both the production of muscle degradation markers and the symptoms of muscle atrophy (loss of lean mass and muscle strength). We also found decreased levels of pro-inflammatory cytokines (IL-6, IFN- γ) and increased levels of anti-inflammatory cytokines (IL-10) in the serum of DEX+JY02-administered mice compared to those in DEX-treated mice. Overall, these results suggest that L. rhamnosus JY02 is a potent probiotic supplement that prevents sarcopenia by suppressing muscle atrophy.

• Journal of Microbiology and Biotechnology
• /
• 제33권12호
• /
• pp.1635-1647
• /
• 2023

Muscle atrophy, which is defined as a decrease in muscle mass and strength, is caused by an imbalance between the anabolism and catabolism of muscle proteins. Thus, modulating the homeostasis between muscle protein synthesis and degradation represents an efficient treatment approach for this condition. In the present study, the protective effects against muscle atrophy of ethanol extracts of Morus alba L. (MA) and Angelica keiskei Koidz. (AK) leaves and their mixtures (MIX) were evaluated in vitro and in vivo. Our results showed that MIX increased 5-aminoimidazole-4-carboxamide ribonucleotide-induced C2C12 myotube thinning, and enhanced soleus and gastrocnemius muscle thickness compared to each extract alone in dexamethasone-induced muscle atrophy Sprague Dawley rats. In addition, although MA and AK substantially improved grip strength and histological changes for dexamethasone-induced muscle atrophy in vivo, the efficacy was superior in the MIX-treated group. Moreover, MIX further increased the expression levels of myogenic factors (MyoD and myogenin) and decreased the expression levels of E3 ubiquitin ligases (atrogin-1 and muscle-specific RING finger protein-1) in vitro and in vivo compared to the MA- and AK-alone treatment groups. Furthermore, MIX increased the levels of phosphorylated phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), and mammalian target of rapamycin (mTOR) that were reduced by dexamethasone, and downregulated the expression of forkhead box O3 (FoxO3a) induced by dexamethasone. These results suggest that MIX has a protective effect against muscle atrophy by enhancing muscle protein anabolism through the activation of the PI3K/Akt/mTOR signaling pathway and attenuating catabolism through the inhibition of FoxO3a.