Leucine-enriched essential amino acids attenuate muscle soreness and improve muscle protein synthesis after eccentric contractions in rats

Abstract

Eccentric exercise results in prolonged muscle weakness and muscle soreness, which are typical symptoms of muscle damage. Recovery from muscle damage is related to mammalian target of rapamycin (mTOR) activity. Leucine-enriched essential amino acids (LEAAs) stimulate muscle protein synthesis via activation of the mTOR pathway. Therefore, we investigated the effect of LEAAs on muscle protein synthesis and muscle soreness after eccentric contractions (EC). Male Sprague–Dawley rats (9–11 weeks old) were administered an LEAA solution (AminoL40; containing 40 % leucine and 60 % other essential amino acids) at 1 g/kg body weight or distilled water (control) 30 min before and 10 min after EC. Tibialis anterior (TA) muscle was exposed to 500 EC by electrical stimulation under anesthesia. The fractional synthesis rate (FSR; %/h) in the TA muscle was measured by incorporating l-[ring-2H5] phenylalanine into skeletal muscle protein. Muscle soreness was evaluated by the paw withdrawal threshold using the Randal–Selitto test with some modifications from 1 to 3 days after EC. The FSR in the EC-control group (0.147 ± 0.016 %/h) was significantly lower than in the sedentary group (0.188 ± 0.016 %/h, p < 0.05). AminoL40 administration significantly mitigated the EC-induced impairment of the FSR (0.172 ± 0.018 %/h). EC decreased the paw withdrawal threshold at 1 and 2 days after EC, which indicated that EC induced muscle soreness. Furthermore, AminoL40 administration alleviated the decreased paw withdrawal threshold. These findings suggest that LEAA supplementation improves the rate of muscle protein synthesis and ameliorates muscle soreness after eccentric exercise.

Effects of branched‐chain amino acids and vitamin D supplementation on physical function, muscle mass and strength, and nutritional status in sarcopenic older adults undergoing hospital‐based rehabilitation: A multicenter randomized controlled trial

“…Leucine is an important trigger of postprandial muscle protein synthesis, and acts through the mammalian target of rapamycin signaling pathway . The consumption of essential amino acids enriched in BCAA, such as leucine, as described in the present trial, increases muscle protein synthesis and alleviates muscle soreness after exercise . Therefore, BCAA and leucine supplementation appear to preserve muscle mass and physical function in sarcopenic older adults with reduced food intake.…”

“…27 The consumption of essential amino acids enriched in BCAA, such as leucine, as described in the present trial, increases muscle protein synthesis and alleviates muscle soreness after exercise. 28 Therefore, BCAA and leucine supplementation appear to preserve muscle mass and physical function in sarcopenic older adults with reduced food intake. Additionally, reversing vitamin D deficiency in combination with BCAA and essential amino acids supplementation might have contributed to the favorable effect on muscle parameters.…”

Whey Protein Supplementation Enhances Whole Body Protein Metabolism and Performance Recovery after Resistance Exercise: A Double-Blind Crossover Study

“…Previous work has suggested that the beneficial effects of protein supplementation on the recovery of force production are independent of muscle damage and oxidative stress [ 61 ]. However, some evidence suggests that essential amino acids may attenuate inflammation/muscle soreness [ 62 , 63 ] and muscle damage [ 64 ] after exercise; if this were to be the case in the present study, then it could have positively impacted all performance tests, including the CMJ movement strategy (pre-load velocity was higher, and eccentric phase shorter, with protein supplementation).…”

Effects and Tolerance of Protein and Energy‐Enriched Formula in Infants Following Congenital Heart Surgery: A Randomized Controlled Trial

“…The positive effect of increasing nutrient intake from high-protein formula can also be reflected by the availability of essential amino acids. Essential amino acids, particularly the branched-chain amino acids (leucine, isoleucine, and valine), have been shown to improve muscle protein synthesis, 12 as well as affect gene expression, 13 protein metabolism, apoptosis and regeneration of hepatocytes, 14 and insulin resistance. 15 As expected, in this study, the PE-group had a significantly higher increase or better maintenance of plasma concentrations of many essential amino acids, especially isoleucine and leucine, compared with the S-group.…”