Streptococcus salivarius subsp. thermophilus ST-G30 Prevents Dexamethasone-Induced Muscle Atrophy in C2C12 Myotubes.

Background/

Objectives

Sarcopenia is characterized by loss of muscle mass and strength and is associated with aging. Recently, its links with the gut-muscle axis have been reported, suggesting that probiotics could influence muscle health.

Methods

In the present study, we investigated the protective roles of two lactic acid bacteria strains, Streptococcus salivarius subsp. thermophilus ST-G30 (ST-G30) and Lacticaseibacillus paracasei LPc-G110 (LPc-G110), on skeletal muscle atrophy induced by dexamethasone (DEX) in C2C12 myotubes.

Results

Our results demonstrated that ST-G30 significantly alleviated DEX-induced myotube atrophy by increasing the myotubes' diameter (25.95 ± 1.28 vs. 15.30 ± 0.30 μm, p < 0.01), improving the fusion index (48.35 ± 1.75 vs. 22.16 ± 2.36%, p < 0.0001), and increasing the protein content (1.78 ± 0.02 vs. 1.56 ± 0.01 mg/mL, p < 0.05) and myotube length (0.61 ± 0.05 vs. 0.33 ± 0.01, p < 0.05), whereas LPc-G110 showed no significant effect on these phenotypes (p > 0.05). Transcriptomic analysis reveals that ST-G30 modulates critical signaling pathways and biological processes related to skeletal muscle health. In the current study, KEGG enrichment analysis and WGCNA enabled identification of the PI3K-Akt signaling pathway as a key regulator of these processes, highlighting its essential role in mitigating DEX-induced muscle atrophy. Furthermore, the overlapping DEGs associated with the PI3K-Akt signaling pathway showed strong correlations with muscle atrophy-related indices.

Conclusions

These findings underscore the potential of ST-G30 as a promising anti-muscle atrophy supplement and provide valuable insights for developing strategies to prevent and treat glucocorticoid-induced skeletal muscle atrophy.