Antarctic krill extracts enhance muscle regeneration and muscle function via mammalian target of rapamycin regulation

Abstract

Sarcopenia is a degenerative disease involving decreases in muscle mass and muscle strength. There is no effective therapeutic target or treatment for sarcopenia. Here, we isolated a new metabolite from Antarctic krill extracts (AKEs) and investigated whether AKEs promote muscle regeneration. The AKEs increased the muscle enhancer-reporter activity of insulin-like growth factor 2 as well as myogenic fusion during C2C12 myoblast differentiation in an mTOR-dependent manner but did not affect the cell cycle or apoptosis. When BaCl2-injured tibialis anterior muscles were injected with the extracts, the central surface area of centrally nucleated regenerating muscle fibers and the grip strength of regenerated muscles were enhanced. Finally, we identified Neicosapentanoyl phenylalanine as the bioactive compound in AKEs using mass spectrometry analysis. Our results suggest that AKEs augment muscle regeneration by increasing mTOR signaling. Thus, the extracts may be useful for developing treatments for sarcopenia.