Effect of a hypergravity environment on cortical bone elasticity in rats

Sean Kohles, J. R. Bowers, A. C. Vailas, R. Vanderby

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

There is considerable interest in determining whether hypergravity can be used as a countermeasure for microgravity-induced bone loss. This study was conducted on 20 immature male rats in order to investigate possible elastic adaptations of cortical bone in rapidly growing rats exposed to chronic hypergravity. Ten rats were continuously centrifuged for 14 days at twice gravitational acceleration (2G) on a 12.75 foot radius centrifuge and 10 rats concurrently acted as stationary controls. The effect of hypergravity on the elastic characteristics of cortical bone was quantified via ultrasonic wave propagation. Propagation velocities of longitudinal and shear waves were measured through cubic cortical specimens from the posterior femoral diaphyses. Density was measured with an Archimedes' technique. The orthotropic elastic properties were calculated and used to compare the difference between groups. Results showed an average increase in both the Young's moduli (Eii, + 2.2%) and shear moduli (Gij, + 4.3%) with a statistically significant increase only in G12 (+15.7%, P = 0.046). The ratio of transverse to axial strain (Poisson's ratio, vij) demonstrated statistically significant changes in v12, v21, v13, and v31 (P <0.05). These findings suggest that although slight elastic changes were incurred via a hyper-gravity environment, the treatment level or duration in this study do not dramatically perturb the normal elastic behavior of cortical bone and that dramatic biomechanical differences noted in previous studies were due more to structural changes than material elasticity changes. Hypergravity applied post facto to a microgravity environment would offer further illucidation of this method as treatment for a degenerative spaceflight experience.

Original languageEnglish (US)
Pages (from-to)214-217
Number of pages4
JournalCalcified Tissue International
Volume59
Issue number3
DOIs
StatePublished - Sep 1996
Externally publishedYes

Fingerprint

Hypergravity
Elasticity
Weightlessness
Diaphyses
Space Flight
Elastic Modulus
Gravitation
Thigh
Bone and Bones
Cortical Bone

Keywords

  • Cortical bone
  • Elastic properties
  • Hypergravity
  • Rats
  • Ultrasonic elasticity

ASJC Scopus subject areas

  • Endocrinology
  • Orthopedics and Sports Medicine
  • Endocrinology, Diabetes and Metabolism

Cite this

Effect of a hypergravity environment on cortical bone elasticity in rats. / Kohles, Sean; Bowers, J. R.; Vailas, A. C.; Vanderby, R.

In: Calcified Tissue International, Vol. 59, No. 3, 09.1996, p. 214-217.

Research output: Contribution to journalArticle

Kohles, Sean ; Bowers, J. R. ; Vailas, A. C. ; Vanderby, R. / Effect of a hypergravity environment on cortical bone elasticity in rats. In: Calcified Tissue International. 1996 ; Vol. 59, No. 3. pp. 214-217.
@article{188acb0d905c41f192c27b5c486db0ac,
title = "Effect of a hypergravity environment on cortical bone elasticity in rats",
abstract = "There is considerable interest in determining whether hypergravity can be used as a countermeasure for microgravity-induced bone loss. This study was conducted on 20 immature male rats in order to investigate possible elastic adaptations of cortical bone in rapidly growing rats exposed to chronic hypergravity. Ten rats were continuously centrifuged for 14 days at twice gravitational acceleration (2G) on a 12.75 foot radius centrifuge and 10 rats concurrently acted as stationary controls. The effect of hypergravity on the elastic characteristics of cortical bone was quantified via ultrasonic wave propagation. Propagation velocities of longitudinal and shear waves were measured through cubic cortical specimens from the posterior femoral diaphyses. Density was measured with an Archimedes' technique. The orthotropic elastic properties were calculated and used to compare the difference between groups. Results showed an average increase in both the Young's moduli (Eii, + 2.2{\%}) and shear moduli (Gij, + 4.3{\%}) with a statistically significant increase only in G12 (+15.7{\%}, P = 0.046). The ratio of transverse to axial strain (Poisson's ratio, vij) demonstrated statistically significant changes in v12, v21, v13, and v31 (P <0.05). These findings suggest that although slight elastic changes were incurred via a hyper-gravity environment, the treatment level or duration in this study do not dramatically perturb the normal elastic behavior of cortical bone and that dramatic biomechanical differences noted in previous studies were due more to structural changes than material elasticity changes. Hypergravity applied post facto to a microgravity environment would offer further illucidation of this method as treatment for a degenerative spaceflight experience.",
keywords = "Cortical bone, Elastic properties, Hypergravity, Rats, Ultrasonic elasticity",
author = "Sean Kohles and Bowers, {J. R.} and Vailas, {A. C.} and R. Vanderby",
year = "1996",
month = "9",
doi = "10.1007/s002239900111",
language = "English (US)",
volume = "59",
pages = "214--217",
journal = "Calcified Tissue International",
issn = "0171-967X",
publisher = "Springer New York",
number = "3",

}

TY - JOUR

T1 - Effect of a hypergravity environment on cortical bone elasticity in rats

AU - Kohles, Sean

AU - Bowers, J. R.

AU - Vailas, A. C.

AU - Vanderby, R.

PY - 1996/9

Y1 - 1996/9

N2 - There is considerable interest in determining whether hypergravity can be used as a countermeasure for microgravity-induced bone loss. This study was conducted on 20 immature male rats in order to investigate possible elastic adaptations of cortical bone in rapidly growing rats exposed to chronic hypergravity. Ten rats were continuously centrifuged for 14 days at twice gravitational acceleration (2G) on a 12.75 foot radius centrifuge and 10 rats concurrently acted as stationary controls. The effect of hypergravity on the elastic characteristics of cortical bone was quantified via ultrasonic wave propagation. Propagation velocities of longitudinal and shear waves were measured through cubic cortical specimens from the posterior femoral diaphyses. Density was measured with an Archimedes' technique. The orthotropic elastic properties were calculated and used to compare the difference between groups. Results showed an average increase in both the Young's moduli (Eii, + 2.2%) and shear moduli (Gij, + 4.3%) with a statistically significant increase only in G12 (+15.7%, P = 0.046). The ratio of transverse to axial strain (Poisson's ratio, vij) demonstrated statistically significant changes in v12, v21, v13, and v31 (P <0.05). These findings suggest that although slight elastic changes were incurred via a hyper-gravity environment, the treatment level or duration in this study do not dramatically perturb the normal elastic behavior of cortical bone and that dramatic biomechanical differences noted in previous studies were due more to structural changes than material elasticity changes. Hypergravity applied post facto to a microgravity environment would offer further illucidation of this method as treatment for a degenerative spaceflight experience.

AB - There is considerable interest in determining whether hypergravity can be used as a countermeasure for microgravity-induced bone loss. This study was conducted on 20 immature male rats in order to investigate possible elastic adaptations of cortical bone in rapidly growing rats exposed to chronic hypergravity. Ten rats were continuously centrifuged for 14 days at twice gravitational acceleration (2G) on a 12.75 foot radius centrifuge and 10 rats concurrently acted as stationary controls. The effect of hypergravity on the elastic characteristics of cortical bone was quantified via ultrasonic wave propagation. Propagation velocities of longitudinal and shear waves were measured through cubic cortical specimens from the posterior femoral diaphyses. Density was measured with an Archimedes' technique. The orthotropic elastic properties were calculated and used to compare the difference between groups. Results showed an average increase in both the Young's moduli (Eii, + 2.2%) and shear moduli (Gij, + 4.3%) with a statistically significant increase only in G12 (+15.7%, P = 0.046). The ratio of transverse to axial strain (Poisson's ratio, vij) demonstrated statistically significant changes in v12, v21, v13, and v31 (P <0.05). These findings suggest that although slight elastic changes were incurred via a hyper-gravity environment, the treatment level or duration in this study do not dramatically perturb the normal elastic behavior of cortical bone and that dramatic biomechanical differences noted in previous studies were due more to structural changes than material elasticity changes. Hypergravity applied post facto to a microgravity environment would offer further illucidation of this method as treatment for a degenerative spaceflight experience.

KW - Cortical bone

KW - Elastic properties

KW - Hypergravity

KW - Rats

KW - Ultrasonic elasticity

UR - http://www.scopus.com/inward/record.url?scp=0029666169&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029666169&partnerID=8YFLogxK

U2 - 10.1007/s002239900111

DO - 10.1007/s002239900111

M3 - Article

VL - 59

SP - 214

EP - 217

JO - Calcified Tissue International

JF - Calcified Tissue International

SN - 0171-967X

IS - 3

ER -