Femoral morphology and cross-sectional geometry of adult myostatin- deficient mice

M. W. Hamrick, A. C. McPherron, C. O. Lovejoy, J. Hudson

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

GDF-8, also known as myostatin, is a member of the transforming growth factor-β (TGF-β) superfamily of secreted growth and differentiation factors that is expressed in vertebrate skeletal muscle. Myostatin functions as a negative regulator of skeletal muscle growth and myostatin null mice show a doubling of muscle mass compared with normal mice. We examined femoral morphology of adult myostatin-deficient mice to assess the effects of muscle fiber hypertrophy and hyperplasia on bone shape and cross-sectional geometry. Femora of age- and weight-matched adult mice homozygous for the disrupted myostatin sequence were compared with those of wild-type controls (n = 8 per group). Results show that, as was the case in previous studies, myostatin null mice have hindlimb muscle masses that are approximately double those of controls. Myostatin-deficient mice exhibit third trochanters that are significantly larger than those of controls, whereas the femoral midshafts of the control and experimental mice do not differ significantly from one another in cortical area, bending moment of inertia, and polar moment of inertia. Our findings indicate that the increased muscle mass of myostatin- deficient mice primarily affects sites of muscle insertion, but does not induce additional cortical bone deposition in the diaphysis relative to controls. We therefore conclude that the expanded third trochanters of myostatin-deficient subjects result from tendon and Sharpey fiber expansion associated with muscle growth rather than cortical bone deposition in response to increased levels of mechanical stress. (C) 2000 by Elsevier Science Inc.

Original languageEnglish (US)
Pages (from-to)343-349
Number of pages7
JournalBone
Volume27
Issue number3
DOIs
Publication statusPublished - Sep 1 2000
Externally publishedYes

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Keywords

  • Bone modeling
  • Bone strength
  • GDF-8
  • Mechanical loading
  • Muscle mass
  • Tendo-osseous junction

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Histology

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