Astragalus polysaccharides decrease muscle wasting through Akt/mTOR, ubiquitin proteasome and autophagy signalling in...

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Radix Astragali polysaccharides (APS) show potential for improving muscle mass.
• Mechanisms underlying APS effects on muscle require further investigation.

Purpose of the Study:

• To investigate the molecular mechanisms of APS in mitigating muscle wasting.
• To evaluate APS effects in a rat model of chronic kidney disease (5/6 nephrectomy).

Main Methods:

• 5/6 nephrectomy or sham operation in Sprague-Dawley rats, treated with or without 2% APS for 155 days.
• Analysis of body weight, muscle fiber characteristics, protein metabolism, inflammatory markers (TNF-α, IL-15, CRP), and oxidative stress markers (MDA, SOD).
• In vivo and in vitro assessment of Akt/mTOR, ubiquitin-proteasome system, autophagy signaling (Atg7, LC3B-II/LC3B-I), and amino acid transporters (SLC38A2).

Main Results:

• APS treatment alleviated weight loss and improved protein metabolism in nephrectomized rats.
• APS normalized serum levels of pro-inflammatory and oxidative stress markers.
• Molecularly, APS restored Akt/mTOR signaling, ubiquitin-proteasome components (MAFbx, MuRF1), autophagy markers (Atg7, LC3B-II/LC3B-I), and SLC38A2 expression.

Conclusions:

• APS ameliorates muscle wasting in nephrectomized rats via modulation of Akt/mTOR, ubiquitin-proteasome, and autophagy pathways.
• SLC38A2 is identified as a potential molecular target for APS-mediated muscle protection.