2024, Vol. 28 ›› Issue (32): 5172-5176

Effect and mechanism of short-chain fatty acids in aged rats with sarcopenia

Xu Rui1, Li Yanyan2, Xu Hong1   

Abstract: BACKGROUND: Studies have shown that short-chain fatty acids (SCFAs) are a potential regulator of skeletal muscle energy metabolism, but the exact mechanism is unclear.
OBJECTIVE: To observe the effect of SCFAs on aged rats with sarcopenia and to explore the underlying mechanism.
METHODS: Sprague-Dawley rats were randomly divided into control group, sarcopenia group, and sarcopenia+SCFAs group (SCFAs group). In the latter two groups, rat models of sarcopenia were established using ovariectomized rats injected with 5 mg/kg dexamethasone for 7 days. In the control group, the abdominal cavity was only exposed but not removed, and then sutured. Rats in the SCFAs group were administered drinking water containing 150 mmol/L short-chain fatty acids, 600 mg/kg sodium acetate, 200 mg/kg sodium propionate, and 200 mg/kg sodium butyrate for 4 weeks. Rats in the control and sarcopenia groups were given the same volume of normal saline. Successful modeling was assessed by measuring the bilateral gastrocnemius muscle mass and body mass to calculate the gastrocnemius index after modeling. Food intake, body mass and grip strength of rats were measured at 0, 1, 2 and 4 weeks after successful modeling; morphological changes of gastrocnemius muscle were observed by hematoxylin-eosin staining; and the expression of p-AMPK and p-ULK1 proteins in gastrocnemius muscle was detected by western blot.
RESULTS AND CONCLUSION: Compared with the control group, the sarcopenia group showed significantly decreased body mass, food intake, forelimb grip strength (P < 0.05), wet mass of gastrocnemius muscle (P < 0.05), and protein levels of p-AMPK and p-ULK1 (P < 0.05). Compared with the sarcopenia group, the SCFAs group showed a significant increase in food intake, body mass, grip strength, wet mass of gastrocnemius muscle, and protein levels of p-AMPK and p-ULK1 in gastrocnemius muscle (P < 0.05). All these findings indicate that SCFAs improve symptoms of sarcopenia in the elderly and may be associated with the upregulation of AMPK and ULK1 proteins in skeletal muscle.

Key words: sarcopenia, AMPK, ULK1, short-chain fatty acids, skeletal muscle, glucolipid metabolism