The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone

Anna Shipov; Paul Zaslansky; Heinrich Riesemeier; Gilad Segev; Ayelet Atkins; Noga Kalish-Achrai; Stephen Weiner; Ron Shahar

doi:10.7717/peerj.10213

The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone

Anna Shipov^*, Paul Zaslansky, Heinrich Riesemeier, Gilad Segev, Ayelet Atkins, Noga Kalish-Achrai, Stephen Weiner, Ron Shahar

^*Corresponding author for this work

The Koret School of Veterinary Medicine

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Abstract

Background. Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone. Methods. Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used. Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation. Results. Cortical bone of both study groups contains two distinct regions: organized circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm³ vs 232 ± 106 µm³, P < 0.001 and 195 ± 86 µm³ vs. 247 ± 106 µm³, P < 0.001, respectively). Lacunar density was also lower in both bone regions of the OVH group (40 ± 18 ×10³ lacunae/mm³ vs. 47 ± 9×10³ lacunae/mm³ in the lamellar region, P = 0.003 and 63 ± 18×10³ lacunae/mm³ vs. 75 ± 13×10³ lacunae/mm³ in the disorganized region, P < 0.001). Vascular canal volume was lower in the disorganized region of the bone in the OVH group compared to the same region in the control group (P < 0.001). Indentation moduli were not different between the study groups in both bone regions. Discussion. Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of these results to humans due to major structural differences between human and rat bone.

Original language	American English
Article number	10213
Journal	PeerJ
Volume	9
DOIs	https://doi.org/10.7717/peerj.10213
State	Published - 13 Jan 2021

Bibliographical note

Funding Information:
The following grant information was disclosed by the authors: German research foundation (DFG): SPP1420. The Helmholtz-Zentrum Berlin by allocation of synchrotron radiation beamtime (proposal 2011_1_101141).

Funding Information:
This work was supported by the German research foundation (DFG) through SPP1420 and the Helmholtz-Zentrum Berlin by allocation of synchrotron radiation beamtime. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Publisher Copyright:
© 2021 PeerJ Inc.. All rights reserved.

Keywords

Disorganized bone
Estrogen
Lacunae
Ovariectomy
Rat

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10.7717/peerj.10213

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title = "The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone",

abstract = "Background. Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone. Methods. Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used. Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation. Results. Cortical bone of both study groups contains two distinct regions: organized circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm3 vs 232 ± 106 µm3, P < 0.001 and 195 ± 86 µm3 vs. 247 ± 106 µm3, P < 0.001, respectively). Lacunar density was also lower in both bone regions of the OVH group (40 ± 18 ×103 lacunae/mm3 vs. 47 ± 9×103 lacunae/mm3 in the lamellar region, P = 0.003 and 63 ± 18×103 lacunae/mm3 vs. 75 ± 13×103 lacunae/mm3 in the disorganized region, P < 0.001). Vascular canal volume was lower in the disorganized region of the bone in the OVH group compared to the same region in the control group (P < 0.001). Indentation moduli were not different between the study groups in both bone regions. Discussion. Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of these results to humans due to major structural differences between human and rat bone.",

keywords = "Disorganized bone, Estrogen, Lacunae, Ovariectomy, Rat",

author = "Anna Shipov and Paul Zaslansky and Heinrich Riesemeier and Gilad Segev and Ayelet Atkins and Noga Kalish-Achrai and Stephen Weiner and Ron Shahar",

note = "Funding Information: The following grant information was disclosed by the authors: German research foundation (DFG): SPP1420. The Helmholtz-Zentrum Berlin by allocation of synchrotron radiation beamtime (proposal 2011_1_101141). Funding Information: This work was supported by the German research foundation (DFG) through SPP1420 and the Helmholtz-Zentrum Berlin by allocation of synchrotron radiation beamtime. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Publisher Copyright: {\textcopyright} 2021 PeerJ Inc.. All rights reserved.",

year = "2021",

month = jan,

day = "13",

doi = "10.7717/peerj.10213",

language = "American English",

volume = "9",

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T1 - The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone

AU - Shipov, Anna

AU - Zaslansky, Paul

AU - Riesemeier, Heinrich

AU - Segev, Gilad

AU - Atkins, Ayelet

AU - Kalish-Achrai, Noga

AU - Weiner, Stephen

AU - Shahar, Ron

N1 - Funding Information: The following grant information was disclosed by the authors: German research foundation (DFG): SPP1420. The Helmholtz-Zentrum Berlin by allocation of synchrotron radiation beamtime (proposal 2011_1_101141). Funding Information: This work was supported by the German research foundation (DFG) through SPP1420 and the Helmholtz-Zentrum Berlin by allocation of synchrotron radiation beamtime. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Publisher Copyright: © 2021 PeerJ Inc.. All rights reserved.

PY - 2021/1/13

Y1 - 2021/1/13

N2 - Background. Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone. Methods. Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used. Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation. Results. Cortical bone of both study groups contains two distinct regions: organized circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm3 vs 232 ± 106 µm3, P < 0.001 and 195 ± 86 µm3 vs. 247 ± 106 µm3, P < 0.001, respectively). Lacunar density was also lower in both bone regions of the OVH group (40 ± 18 ×103 lacunae/mm3 vs. 47 ± 9×103 lacunae/mm3 in the lamellar region, P = 0.003 and 63 ± 18×103 lacunae/mm3 vs. 75 ± 13×103 lacunae/mm3 in the disorganized region, P < 0.001). Vascular canal volume was lower in the disorganized region of the bone in the OVH group compared to the same region in the control group (P < 0.001). Indentation moduli were not different between the study groups in both bone regions. Discussion. Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of these results to humans due to major structural differences between human and rat bone.

AB - Background. Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone. Methods. Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used. Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation. Results. Cortical bone of both study groups contains two distinct regions: organized circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm3 vs 232 ± 106 µm3, P < 0.001 and 195 ± 86 µm3 vs. 247 ± 106 µm3, P < 0.001, respectively). Lacunar density was also lower in both bone regions of the OVH group (40 ± 18 ×103 lacunae/mm3 vs. 47 ± 9×103 lacunae/mm3 in the lamellar region, P = 0.003 and 63 ± 18×103 lacunae/mm3 vs. 75 ± 13×103 lacunae/mm3 in the disorganized region, P < 0.001). Vascular canal volume was lower in the disorganized region of the bone in the OVH group compared to the same region in the control group (P < 0.001). Indentation moduli were not different between the study groups in both bone regions. Discussion. Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of these results to humans due to major structural differences between human and rat bone.

KW - Disorganized bone

KW - Estrogen

KW - Lacunae

KW - Ovariectomy

KW - Rat

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JO - PeerJ

JF - PeerJ

M1 - 10213

ER -

The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone

Abstract

Bibliographical note

Keywords

UN SDGs

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