Resistance exercise with anti-inflammatory foods attenuate skeletal muscle atrophy induced by chronic inflammation.

Chronic inflammation (CI) can contribute to muscle atrophy and sarcopenia. Resistance exercise (RE) promotes increased and/or maintenance of skeletal muscle mass, but the effects of RE in the presence of CI are unclear. In this study, we developed a novel animal model of CI-induced muscle atrophy and examined the effect of acute or chronic RE by electrical stimulation. CI was induced in young female Lewis rats by injection with peptidoglycan-polysaccharide (PG-PS). ERK, p70S6K, 4E-BP1, Akt and FOXO1 phosphorylation levels increased in Gastrocnemius (Gas) muscle from normal rats subjected to acute RE. Following acute RE in CI rats, increased levels of phosphorylated ERK, p70S6K and 4E-BP1, but not Akt and FOXO1, were observed. Chronic RE significantly increased the Gas weight in the exercised limb relative to the non-trained opposing limb in CI rats. Dietary supplementation with anti-inflammatory agents, EPA/DHA and α-lactalbumin attenuated CI-induced muscle atrophy in the untrained Gas and could promote RE-induced inhibition of atrophy in the trained Gas. In the trained leg, significant negative correlations (r ≤ -0.80) were seen between Gas weights and CI indices, including proinflammatory cytokines and white blood cell count. These results indicated that the anabolic effects of RE are effective to prevent CI-induced muscle atrophy but are partially attenuated by inflammatory molecules. The findings also suggested that anti-inflammatory treatment together with RE is an effective intervention for muscle atrophy induced by CI. Taken together, we conclude that systemic inflammation levels are associated with skeletal muscle protein metabolism and plasticity.