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Dietary Nitrate and Skeletal Muscle Recovery after Injury in Young and Old Mice
Author(s) -
Hahn Dongwoo,
Patel Ravi,
Kelley Rachel C,
Coblentz Philip D,
Ferreira Leonardo F
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.713.3
Subject(s) - cardiotoxin , skeletal muscle , nitric oxide , medicine , endocrinology , chemistry , muscle hypertrophy , saline , extensor digitorum longus muscle , myosin , anatomy , biochemistry
Nitric oxide availability has been shown to modulate skeletal muscle hypertrophy and regeneration post‐injury. Aging decreases nitric oxide availability and delays skeletal muscle recovery from injury. Dietary nitrate increases nitric oxide availability in skeletal muscle vessels and fibers. However, it is unclear whether dietary nitrate can accelerate aged skeletal muscle regeneration post‐injury. Therefore, our goal was to investigate the effect of dietary nitrate on skeletal muscle recovery from injury in aging. Young (n=36, 6 months old) and old (n=20, 24 months old) mice received sodium nitrate (NaNO 3 , 1mM) in drinking water or vehicle (deionized H 2 O) ad libitum for a total of 14 days. Seven days after the start of treatment, we injected cardiotoxin (CTX, 10 μM) into the tibialis anterior (TA) and extensor digitorum longus (EDL) from one limb, and saline into muscles of the contralateral limb. Seven days post‐injection, we collected the TA and EDL for measurements of muscle force, morphology, protein and mRNA. CTX decreased TA and EDL weights by ~30% each (p < 0.05), and the effects were independent of age or treatment. CTX decreased EDL maximal tetanic absolute (mN) and specific force (N/cm 2 ) by 65% and 50% (P < 0.05 vs. non‐injected controls), respectively, and the effects were independent of age or treatment. CTX increased protein abundance of myogenin in the TA, an effect that was independent of age or treatment. Dietary NaNO 3 decreased protein levels of embryonic myosin heavy chain (eMHC) in saline‐injected TA of old animals, whereas eMHC protein abundance increased after CTX injection. Protein levels of eMHC in CTX‐injected TA of animals receiving NaNO 3 were similar to those from CTX‐ and saline‐injected muscles of old mice drinking vehicle. Overall, our data heretofore suggest that dietary NaNO 3 did not accelerate the recovery of skeletal muscle force and weight, or markers of myogenesis in young and old animals. An interesting observation was that dietary NaNO 3 decreased the levels of eMHC in saline‐injected muscle from old animals. Support or Funding Information NIA R03 AG040400‐02