Effect of a growth hormone treatment on bone orthotropic elasticity in dwarf rats

Sean S. Kohles, Daniel A. Martinez, James R. Bowers, Arthur C. Vailas, Ray Vanderby

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

A refinement of the current ultrasonic elasticity technique was used to measure the orthotropic elastic properties of rat cortical bone as well as to quantify changes in elastic properties, density, and porosity of the dwarf rat cortex after a treatment with recombinant human growth hormone (rhGH). The ultrasonic elasticity technique was refined via optimized signal management of high-frequency wave propagation through cubic cortical specimens. Twenty dwarf rats (37 days old) were randomly assigned to two groups (10 rats each). The dwarf rat model (5-10% of normal GH) was given subcutaneous injections of either rhGH or saline over a 14-day treatment period. Density was measured using Archimedes' technique. Porosity and other microstructural characteristics were also explored via scanning electron microscopy and image analysis. Statistical tests verified significant decreases in cortical orthotropic Young's (-26.7%) and shear (-16.7%) moduli and density (-2.42%) concomitant with an increase in porosity (+125%) after rhGH treatments to the dwarf model (p<0.05). A change in material symmetry from orthotropy toward planar isotropy within the radial-circumferential plane after GH treatments was also noted. These results demonstrate some alteration in bone properties at this time interval. Structural implications of these changes throughout physiological loading regimens should be explored.

Original languageEnglish (US)
Pages (from-to)77-85
Number of pages9
JournalAnnals of Biomedical Engineering
Volume25
Issue number1
DOIs
StatePublished - 1997

Keywords

  • Cortical bone
  • Dwarfism
  • Growth hormone
  • Rat model
  • Ultrasonic elasticity

ASJC Scopus subject areas

  • Biomedical Engineering

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