Effects of a Plant-Derived Protein Diet Supplemented With Multi-Strain Probiotics on Muscle Mass, Muscle Strength, and Gut Microbiota in Aged Rats

This study examined whether a plant-derived protein diet combined with multi-strain probiotics protects against sarcopenia in naturally aged rats (21 months old) via the gut-muscle axis following a 12-week intervention.Compared with the aged control group,The combined intervention increased grip strength by 55.96%, gastrocnemius index by 23.49%, and quadriceps index by 28.29%, while reducing oxidative stress and inflammation (MDA by 39.80%, TNF-α by 42.19%, IL-6 by 65.81%). Mechanistically, it enhanced gut microbiota diversity, enriched beneficial taxa (e.g., Alistipes, Lachnospiraceae_UCG-006), elevated fecal SCFAs, modulated serum amino acids, and upregulated muscle synthesis-related proteins (AMPK-α1, p70 S6K). These findings suggest that a plant-derived protein diet supplemented with multi-strain probiotics represents a promising nutritional strategy to counteract age-related sarcopenia and support healthy ageing.