Twenty-four 25-month-old rats were fed either a control diet (OC), an oleate-enriched diet (HFO) or a palmitate-enriched diet (HFP) for 16 weeks. MPS using labeled amino acids and mTOR activation were assessed after AA and insulin anabolic stimulation to mimic postprandial state.
IR and systemic and adipose tissue inflammation (TNF¦Á and IL1¦Â) were improved in the HFO group. Muscle genes controlling mitochondrial ¦Â-oxidation (PPARs, MCAD and CPT-1b) were up-regulated in the HFO group. AA and insulin-stimulated MPS in the HFO group only, and this stimulation was related to activation of the Akt/mTOR pathway.
The age-related MPS response to anabolic signals was improved in rats fed an oleate-enriched diet. This effect was related to activation of muscle oxidative pathways, lower IR, and a decrease in inflammation.