Effects of eccentric exercise on branched-chain amino acid profiles in rat serum and skeletal muscle

Supplementation of branched-chain amino acid (BCAA) is often used to attenuate exercise-induced skeletal muscle damage and promote adaptation, but no definitive conclusion on the benefits of BCAA on muscle recovery after injurious exercise can be drawn. Exploration of the systematic BCAA alteration in muscular injury-repair stage per se without any BCAA supplement should provide some useful information in favour of BCAA application in muscle regeneration after injury. One bout of 90-min downhill-running exercise was performed to cause rat skeletal muscle injury. After exercise, myofibrillar BCAA concentrations showed minor changes compared with exercise before, while serum concentrations of BCAA were lower after exercise. Especially, serum leucine, isoleucine and total BCAA concentrations 2weeks post-run were significantly lower than normal values of exercise before (p=0.008, p=0.041, p=0.015). The data demonstrate that a single eccentric exercise can significantly decrease the serum BCAA concentrations, which mean high utilization of BCAA for myogenesis after injurious exercise.