Study on effect mechanism of Shanyu Pills in improving skeletal muscle mass and motor function in sarcopenia mice based on gastrocnemius muscle metabolomics

This study evaluated the effects of Shanyu Pills on the skeletal muscle mass, motor function, and metabolites of the gastrocnemius muscle in sarcopenia mice, aiming to explore the scientific essence of Shanyu Pills in treating sarcopenia. All animal experiments were approved by the Experimental Animal Ethics Committee of Fujian University of Traditional Chinese Medicine (approval No.: FJTCM IACUC 2022123). Eight-month-old rapidly aging mice SAMP8 (senescence accelerated mouse prone/8, SAMP8) were used as the animal model for sarcopenia. The biological effects of Shanyu Pills in improving the skeletal muscle mass and motor function of mice with sarcopenia were evaluated by evaluating of the degree of senescence of mice, muscle volume of the hindlimbs, grip strength, hanging net duration time, rotarod performance time, free movement assessment, biochemical indicators of spleen deficiency, and histopathology of gastrocnemius muscle tissue. The metabolites in the gastrocnemius muscle of mice were analyzed using LC-MS/MS. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) was used to screen out the differential metabolites among different comparison groups. The differential metabolites were analyzed for metabolic pathway enrichment using the MetaboAnalyst 6.0 database and the "Compound-Reaction-Enzyme-Gene" network of the differential metabolites was constructed using Cytoscape 3.10.0 software. The results showed that Shanyu Pills could significantly reduce the degree of senescence of sarcopenia mice; increase the muscle volume of the hindlimbs, grip strength, hanging net duration time, rotarod performance time, free movement assessment; improve the biochemical indicators of spleen deficiency; and alleviate the phenomenon of gastrocnemius muscle fiber atrophy. The non-targeted metabolomics analysis of the gastrocnemius muscle showed that Shanyu Pills mainly affected 14 differential metabolites such as arachidonic acid, leukotriene A4, carnosine, methylimidazoleacetic acid. The potential target metabolic pathways enriched were the arachidonic acid metabolic pathway. In summary, Shanyu Pills can effectively improve the skeletal muscle mass and motor function of sarcopenia mice, and its mechanism may be closely related to the regulation of arachidonic acid metabolism.