Molecules and Cells

, Volume 34, Issue 5, pp 439–448

β-hydroxy-β-methylbutyrate did not enhance high intensity resistance training-induced improvements in myofiber dimensions and myogenic capacity in aged female rats

  • Jeong-Su Kim
  • Young-Min Park
  • Sang-Rok Lee
  • Ihssan S. Masad
  • Andy V. Khamoui
  • Edward Jo
  • Bong-Sup Park
  • Bahram H. Arjmandi
  • Lynn B. Panton
  • Won Jun Lee
  • Samuel C. Grant
Article

DOI: 10.1007/s10059-012-0196-x

Cite this article as:
Kim, J., Park, Y., Lee, S. et al. Mol Cells (2012) 34: 439. doi:10.1007/s10059-012-0196-x

Abstract

Older women exhibit blunted skeletal muscle hypertrophy following resistance training (RT) compared to other age and gender cohorts that is partially due to an impaired regenerative capacity. In the present study, we examined whether β-hydroxy-β-methylbutyrate (HMB) provision to aged female rodents would enhance regenerative mechanisms and facilitate RT-induced myofiber growth. Nineteen-month old female Sprague-Dawley rats were randomly divided into three groups: HMB (0.48 g/kg/d; n = 6), non-HMB (n = 6), and control (n = 4). HMB and non-HMB groups underwent RT every third day for 10 weeks using a ladder climbing apparatus. Whole body strength, grip strength, and body composition was evaluated before and after RT. The gastrocnemius and soleus muscles were analyzed using magnetic resonance diffusion tensor imaging, RT-PCR, and immunohistochemistry to determine myofiber dimensions, transcript expression, and satellite cells/myonuclei, respectively. ANOVAs were used with significance set at p < 0.05. There were significant time effects (pre vs. post) for whole body strength (+262%), grip strength (+17%), lean mass (+20%), and fat mass (−19%). Both RT groups exhibited significant increases in the mean myofiber cross-sectional area (CSA) in the gastrocnemius and soleus (+8−22%) compared to control. Moreover, both groups demonstrated significant increases in the numbers of satellite cells (+100−108%) and myonuclei (+32%) in the soleus but not the gastrocnemius. A significant IGF-I mRNA elevation was only observed in soleus of the HMB group (+33%) whereas MGF and myogenin increased significantly in both groups (+32−40%). Our findings suggest that HMB did not further enhance intense RT-mediated myogenic mechanisms and myofiber CSA in aged female rats.

Copyright information

© The Korean Society for Molecular and Cellular Biology and Springer Netherlands 2012

Authors and Affiliations

  • Jeong-Su Kim
    • 1
    • 2
  • Young-Min Park
    • 1
  • Sang-Rok Lee
    • 1
  • Ihssan S. Masad
    • 3
  • Andy V. Khamoui
    • 1
    • 2
  • Edward Jo
    • 1
    • 2
  • Bong-Sup Park
    • 1
  • Bahram H. Arjmandi
    • 1
    • 2
  • Lynn B. Panton
    • 1
    • 2
  • Won Jun Lee
    • 1
    • 4
  • Samuel C. Grant
    • 2
    • 3
  1. 1.Department of Nutrition, Food, and Exercise SciencesThe Florida State UniversityTallahasseeUSA
  2. 2.The Center for Advancing Exercise and Nutrition Research on AgingThe Florida State UniversityTallahasseeUSA
  3. 3.The National High Magnetic Field Laboratory and Department of Chemical and Biomedical EngineeringThe Florida State UniversityTallahasseeUSA
  4. 4.Department of Exercise ScienceEwha Womans UniversitySeoulKorea