Pomegranate extract prevents skeletal muscle of mice against wasting induced by acute TNF-α injection

Scope: We investigated whether punicalagin-rich pomegranate extract (PE) protects skeletal muscle of mice against inflammation induced by an acute injection of TNF-alpha. Results: Mice fed with PE or standard chow during 6 wk were injected with TNF-alpha (100 ng/g) or vehicle and sacrificed 6 h later. Prior supplementation with PE prevented the loss of tibialis anterior mass induced by TNF-alpha. In skeletal muscle, the activation of the NF-kappa B signaling and the induction of cytokines mRNA were reduced in mice having received PE. In those mice, the activity of the Akt/mTORC1 pathway and the protein synthesis were maintained after TNF-alpha injection whereas markers involved in the ubiquitin proteasome pathway were less activated. As urolithin A was the only punicalaginmetabolite detectable in plasma ofmice supplemented with PE, we performed in vitro experiments using a murine cell line (C2C12) to provide evidence that urolithin A is likely the active compound protecting skeletalmuscle against TNF-alpha-induced inflammation. Conclusion (focus on nutritional relevance): These results suggest that supplementation with a punicalagin-rich PE may protect skeletal muscle against an acute inflammation.