Muscle strength and size are associated with motor unit connectivity in aged mice

NEUROBIOLOGY OF AGING

卷:67

Article

Sheth, Kajri A.¹  Iyer, Chitra C.^1,2  Wier, Christopher G.^1,2  Crum, Alexander E.¹  Bratasz, Anna³  Kolb, Stephen J.^1,2  Clark, Brian C.⁴  Burghes, Arthur H. M.^1,2  Arnold, W. David^1,5,6,7 

[1] Ohio State Univ, Dept Neurol, Columbus, OH 43210 USA

[2] Ohio State Univ, Dept Biol Chem & Pharmacol, Columbus, OH 43210 USA

[3] Ohio State Univ, Wexner Med Ctr, Small Anim Imaging Core, Columbus, OH 43210 USA

[4] Ohio Univ, Ohio Musculoskeletal & Neurol Inst, Athens, OH 45701 USA

[5] Ohio State Univ, Dept Phys Med & Rehabil, Columbus, OH 43210 USA

[6] Ohio State Univ, Dept Neurosci, Columbus, OH 43210 USA

[7] Ohio State Univ, Dept Physiol & Cell Biol, Columbus, OH 43210 USA

关键词: Dynapenia;    Sarcopenia;    Motor unit;    Electrophysiology;    Aging;    Denervation;   

DOI  :  10.1016/j.neurobiolaging.2018.03.016

来源: Elsevier

【 摘 要 】

In older adults, the loss of muscle strength (dynapenia) and the loss of muscle mass (sarcopenia) are important contributors to the loss of physical function. We sought to investigate dynapenia, sarcopenia, and the loss of motor unit function in aging mice. C57BL/6J mice were analyzed with cross- sectional (males: 3 vs. 27 months; males and females: 8 vs. 12 vs. 20 months) and longitudinal studies (males: 10-25 months) using in vivo electrophysiological measures of motor unit connectivity (triceps surae compound muscle action potential and motor unit number estimation), in vivo measures of plantar flexion torque, magnetic resonance imaging of hind limb muscle volume, and grip strength. Compound muscle action potential amplitude, motor unit number estimation, and plantar flexion torque were decreased at 20 months. In contrast, grip strength was reduced at 24 months. Motor unit number estimates correlated with muscle torque and hind limb muscle volume. Our results demonstrate that the loss of motor unit connectivity is an early finding in aging male and female mice and that muscle size and contractility are both associated with motor unit number. (C) 2018 The Author(s). Published by Elsevier Inc.

【 授权许可】

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