Differences of three-dimensional trabecular microstructure in osteopenic rat models caused by ovariectomy and neurectomy

Ito, Masako; Nishida, Akifumi; Nakamura, Toshio; Uetani, Masataka; Hayashi, Kuniaki

doi:10.1016/s8756-3282(02)00684-1

Cited by 82 publications

(53 citation statements)

References 14 publications

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“…The lower reduction of epiphyseal BV/TV after estrogen deficiency concurs with previous reports. 17,30 A study comparing decreases in trabecular BV/TV after estrogen deficiency also reported greater reductions in the metaphysis after 4 weeks. 17 The untreated leg of the NX rats was also scanned (data not shown).…”

Section: Discussionmentioning

confidence: 99%

“…17,30 A study comparing decreases in trabecular BV/TV after estrogen deficiency also reported greater reductions in the metaphysis after 4 weeks. 17 The untreated leg of the NX rats was also scanned (data not shown). We expected loads in the untreated leg to be higher and therefore adaptation to take place in the form of increased BV/TV.…”

Section: Discussionmentioning

confidence: 99%

“…[9][10][11][12][13][14][15][16][17] After estrogen deficiency, bone loss is concentrated in the central part of the metaphysis, whereas disuse leads to overall bone loss. 11,13,17 This finding supports the hypothesis that OVX-induced estrogen deficiency increases the mechanostat threshold, 9 leading to low loaded regions being resorbed first, whereas the main loaded structures would remain. With disuse, however, all bone tissue is unloaded, so a more random pattern of bone loss would be expected.…”

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confidence: 99%

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Comparison of bone loss induced by ovariectomy and neurectomy in rats analyzed by in vivo micro‐CT

Brouwers

Lambers

Rietbergen

et al. 2009

Journal Orthopaedic Research

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ABSTRACT:We hypothesized that osteoporosis due to estrogen deficiency progresses faster than due to disuse and that at the same amount of bone loss, disuse leads to less favorable bone structure and mechanical properties than estrogen deficiency. Adult rats were either ovariectomized (OVX) (n ¼ 9) or neurectomized (NX) (n ¼ 8). At week 0, 1, 2, 3, and 4, in vivo micro-CT scans were made of the proximal tibia. Segmented CT-scans at weeks 0 and 4 were used to build a 3D voxel-based micro finite element model (FEM). Displacement in the longitudinal direction was prescribed at the proximal end leading to a compression step of 1%. The severe reduction in metaphyseal bone volume fraction was not significantly different between OVX and NX. Epiphyseal bone loss was less severe in both groups, and BV/TV was significantly lower after NX. Trabecular separation and degree of anisotropy in the metaphysis and connectivity and trabecular number in the epiphysis were significantly more deteriorated after NX. FEM-derived stiffness decreased in both groups, but more after NX. Osteoporosis due to estrogen-deficiency progressed overall at a rate similar to osteoporosis due to disuse. At the same amount of induced bone loss, disuse led to more deteriorated bone structure and mechanical properties than estrogen deficiency. Keywords: estrogen deficiency; disuse; osteoporosis; rats; in vivo micro-CT Osteoporosis is a degenerative bone disease that can develop with reduced estrogen levels during and after menopause and after long periods of disuse. The rat has been used to study osteoporosis, with estrogen deficiency-associated bone loss induced by ovariectomy (OVX), 1-4 and disuse-associated bone loss induced by sciatic neurectomy (NX), tail suspension, or leg taping. 5,6 Both can severely deteriorate bone structure in these models. Differences exist in cellular activity with these forms of bone loss. 7,8 OVX leads to an increased bone formation and resorption rate, disuse leads to decreased turnover rates and increased bone resorption. [9][10][11] This would suggest that bone loss after OVX might proceed faster than that resulting from disuse.Differences also exist in the resulting deterioration of bone mass and microstructure. 9-17 After estrogen deficiency, bone loss is concentrated in the central part of the metaphysis, whereas disuse leads to overall bone loss. 11,13,17 This finding supports the hypothesis that OVX-induced estrogen deficiency increases the mechanostat threshold, 9 leading to low loaded regions being resorbed first, whereas the main loaded structures would remain. With disuse, however, all bone tissue is unloaded, so a more random pattern of bone loss would be expected. 9 This would suggest that disuse-induced osteoporosis would lead to a more severe loss of the main trabecular structures and thus a more severe loss of stiffness and strength in the main loading direction. Upon reloading, distribution of loads in immobilized bones would be very inhomogeneous, because the adaptation to the loading direction is lost. ...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Comparison of bone loss induced by ovariectomy and neurectomy in rats analyzed by in vivo micro‐CT

Brouwers

Lambers

Rietbergen

et al. 2009

Journal Orthopaedic Research

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“…Examples of this type of relationship include the connection between the microstructure of a porous medium and the fluid flow characteristics through it, the microstructure of cheese and its textural characteristics [1], the organization of lipids in the skin and the rate of transdermal transport of drug molecules [2], and the cavity size distribution in bone and the onset of osteoporosis [3]. Although one can extract valuable information about a material by viewing an image of it, the visualization process is qualitative in nature, and thus results obtained from such a process will always possess a degree of subjectivity.…”

Section: Introductionmentioning

confidence: 99%

Quantification of order in the Lennard-Jones system

Errington

Debenedetti

Torquato

2003

The Journal of Chemical Physics

135

136

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We conduct a numerical investigation of structural order in the shifted-force Lennard-Jones system by calculating metrics of translational and bond-orientational order along various paths in the phase diagram covering equilibrium solid, liquid, and vapor states. A series of non-equilibrium configurations generated through isochoric quenches, isothermal compressions, and energy minimizations are also considered. Simulation results are analyzed using an ordering map representation [Torquato et al., Phys. Rev. Lett. 84, 2064(2000; Truskett et al., Phys. Rev. E 62, 993 (2000)] that assigns to both equilibrium and non-equilibrium states coordinates in an order metric plane. Our results show that bond-orientational order and translational order are not independent for simple spherically symmetric systems at equilibrium. We also demonstrate quantitatively that the Lennard-Jones and hard sphere systems sample the same configuration space at supercritical densities. Finally, we relate the structural order found in fast-quenched and minimum-energy configurations (inherent structures).

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“…Histomorphometry, despite its very high resolution, is a destructive and time-consuming method. Alternatively, micro-computed tomography (lCT) is fully nondestructive and well-suited for assessing truly threedimensional (3D) microstructural bone properties [16][17][18][19][20][21]. Previous studies have shown lCT to be an accurate technique, with close correlations between microtomographic and histomorphometric measurements of static structural bone metrics in various applications [22][23][24][25][26].…”

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confidence: 99%

Differential Effects of Bone Structural and Material Properties on Bone Competence in C57BL/6 and C3H/He Inbred Strains of Mice

2008

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The femoral neck is a relevant and sensitive site for studying the degree of osteopenia. Engineering principles predict that bone structural parameters, like cross-sectional geometry, are important determinants of bone mechanical parameters. Mechanical parameters are also directly affected by the material properties of the bone tissue. However, the relative importance of structural and material properties is still unknown. The aim of this study was to compare bone competence and structural parameters between a murine strain showing a low bone mass phenotype, C57BL/6 (B6), and another one showing a high bone mass phenotype, C3H/He (C3H), in order to better determine the role of bone structure and geometry in bone failure behavior. Murine femora of 12-and 16-week-old B6 and 12-and 16-week-old C3H inbred strains were mechanically tested under axial loading of the femoral head. In order to assess the structural properties, we performed three-dimensional morphometric analyses in five different compartments of the mouse femur using micro-computed tomography. The mechanical tests revealed that B6 femora became stiffer, stronger, and tougher at 12-16 weeks, while bone brittleness stayed constant. C3H bone stiffness increased, but strength remained constant, work to failure decreased, and bone became more brittle. These age effects indicated that B6 did not reach peak bone properties at 16 weeks of age and C3H did reach maximal skeletal biomechanical properties before 16 weeks of age. Our investigations showed that 83% of the strength of the femoral neck in the B6 strain was explained by cortical thickness at this location; in contrast, in C3H none of the mechanical properties of the femoral neck was explained by bone structural parameters. The relative contributions of bone structural and material properties on bone strength are different in B6 and C3H. We hypothesize that these different contributions are related to differences at the ultrastructural level of bone that affect bone failure.

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Differences of three-dimensional trabecular microstructure in osteopenic rat models caused by ovariectomy and neurectomy

Cited by 82 publications

References 14 publications

Comparison of bone loss induced by ovariectomy and neurectomy in rats analyzed by in vivo micro‐CT

Comparison of bone loss induced by ovariectomy and neurectomy in rats analyzed by in vivo micro‐CT

Quantification of order in the Lennard-Jones system

Differential Effects of Bone Structural and Material Properties on Bone Competence in C57BL/6 and C3H/He Inbred Strains of Mice

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