Journal
JOURNAL OF NUTRITION
Volume 145, Issue 5, Pages 900-906Publisher
AMER SOC NUTRITION-ASN
DOI: 10.3945/jn.114.203737
Keywords
disuse; immobilization; amino acids; muscle atrophy; muscle force; autophagy; muscle breakdown
Categories
Funding
- Ajinomoto Amino Acid Research Program [3ARP: 09/07]
Ask authors/readers for more resources
Background: Increasing arginine (Arg) availability reduces atrophy in cultured skeletal muscle cells. Supplementation with its metabolic precursor citrulline (Cit) is more effective at improving skeletal muscle Arg concentrations. Objective: We tested the hypothesis that Cit supplementation would attenuate skeletal muscle atrophy and loss of function during hindlimb immobilization in mice. Methods: Male C57BL/6JArc mice underwent 14 d of unilateral hindlimb immobilization/plaster casting and were supplemented with similar to 0.81 g Cit center dot kg(-1) center dot d(-1) (CIT group) or Ala (ALA group) mixed into their food. The uncasted contralateral limb (internal control) and an uncasted group (CON) served as controls. Muscle atrophy was evaluated with mass, fiber area, and in situ muscle function. Results: Tibialis anterior (TA) muscle mass [ALA: 37.6 +/- 0.92 mg; CIT: 38.3 +/- 1.25 mg] and peak tetanic force (ALA: 1150 +/- 38.5 mN; CIT: 1150 +/- 52.0 mN) were lower (P < 0.001) in the ALA (53.9 +/- 0.42 mg) and CIT (1760 +/- 28 5 mN) groups than in the CON group. No difference was found between ALA and CIT groups for TA mass, fiber area, or peak force. The mRNA expression of the nitric oxide synthase 2, inducible (Nos2; similar to 15-fold) and B-cell chronic lymphoid leukemia/lymphoma 2/adenovirus El B 19 kDa interacting protein 3 (Bnip3; similar to 17-fold) genes and the ratio of microtubule-associated protein light chain 3BII to 3BI (LC3BII:LC3BI) (50.5% +/- 17.7%) were higher (P< 0.05) in the ALA group than in the CON group,. suggesting increased autophagy. In the CIT group, Bnip3 mRNA was lower (-70%; P < 0.05) and Nos2 mRNA tended to be lower (-45%; P = 0.05) than in the ALA group, whereas LC3BII:LC3BI was not different from the CON group. Conclusions: Cit treatment of male mice did not affect therapeutically relevant outcome measures such as skeletal muscle mass and peak muscle force after 14 d of hindlimb immobilization.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available