Determination of femur structural properties by geometric and material variables as a function of body weight in rats. Evidence of a sexual dimorphism

Ferretti, J.L.; Capozza, Ricardo Francisco; Mondelo, N; Montuori, E; Zanchetta, José R.

doi:10.1016/8756-3282(93)90150-9

Cited by 45 publications

(31 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The mechanical properties were estimated using threepoint bending test in INSTRON 4302 apparatus connected to a computer and registering the relationship between force acting perpendicularly to the longitudinal bone axis and resulting displacement [13,14]. The results of the mechanical analysis were presented graphically and the maximum elastic strength (Wy) and the ultimate strength were estimated (Wf).…”

Section: Analysis Of the Geometric And Mechanical Parametersmentioning

confidence: 99%

“…Geometric parameters such as the cross sectional area (A) and the mean relative wall thickness (MRWT) were derived on the basis of the measurement of the external and internal horizontal and vertical diameters in the middle of the shaft of the humerus [13,14]. The mechanical properties were estimated using threepoint bending test in INSTRON 4302 apparatus connected to a computer and registering the relationship between force acting perpendicularly to the longitudinal bone axis and resulting displacement [13,14].…”

Section: Analysis Of the Geometric And Mechanical Parametersmentioning

confidence: 99%

See 1 more Smart Citation

Effect of maternal dexamethasone and alpha-ketoglutarate administration on skeletal development during the last three weeks of prenatal life in pigs

Sliwa¹,

Tatara²,

Nowakowski³

et al. 2006

The Journal of Maternal-Fetal & Neonatal Medicine

View full text Add to dashboard Cite

show abstract

Section: Analysis Of the Geometric And Mechanical Parametersmentioning

confidence: 99%

Section: Analysis Of the Geometric And Mechanical Parametersmentioning

confidence: 99%

Effect of maternal dexamethasone and alpha-ketoglutarate administration on skeletal development during the last three weeks of prenatal life in pigs

Sliwa¹,

Tatara²,

Nowakowski³

et al. 2006

The Journal of Maternal-Fetal & Neonatal Medicine

View full text Add to dashboard Cite

show abstract

“…The bony geometry was determined from the x-ray film of a specimen. The material properties used were: Elastic modulus 7 GPa, Poisson's ratio 0.3 for cortical bone, and elastic modulus 0.9 GPa, Poisson's ratio ϭ 0.3 for cancellous bone (33). The joint force was assumed as 1.64 N, which was about one-third of an average rat body weight (500 g).…”

Section: Methodsmentioning

confidence: 99%

Estrogen regulates the rate of bone turnover but bone balance in ovariectomized rats is modulated by prevailing mechanical strain

Westerlind

Wronski

Ritman

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

176

141

View full text Add to dashboard Cite

Estrogen deficiency induced bone loss is associated with increased bone turnover in rats and humans. The respective roles of increased bone turnover and altered balance between bone formation and bone resorption in mediating estrogen deficiency-induced cancellous bone loss was investigated in ovariectomized rats. Ovariectomy resulted in increased bone turnover in the distal femur. However, cancellous bone was preferentially lost in the metaphysis, a site that normally experiences low strain energy. No bone loss was observed in the epiphysis, a site experiencing higher strain energy. The role of mechanical strain in maintaining bone balance was investigated by altering the strain history. Mechanical strain was increased and decreased in long bones of ovariectomized rats by treadmill exercise and functional unloading, respectively. Functional unloading was achieved during orbital spacef light and following unilateral sciatic neurotomy. Increasing mechanical loading reduced bone loss in the metaphysis. In contrast, decreasing loading accentuated bone loss in the metaphysis and resulted in bone loss in the epiphysis. Finally, administration of estrogen to ovariectomized rats reduced bone loss in the unloaded and prevented loss in the loaded limb following unilateral sciatic neurotomy in part by reducing indices of bone turnover. These results suggest that estrogen regulates the rate of bone turnover, but the overall balance between bone formation and bone resorption is inf luenced by prevailing levels of mechanical strain.Ovarian hormone deficiency is the most important risk factor for postmenopausal osteoporosis (1, 2). Bone loss also occurs in premenopausal women following ovariectomy (OVX) (3) or treatment with gonadotrophin-releasing hormone agonists (4). Estrogen replacement therapy prevents bone loss in postmenopausal and ovariectomized women, suggesting that 17␤-estradiol is the gonadal hormone that is essential for normal bone balance.The mechanism for the skeletal effects of estrogen are incompletely understood but have been the subject of intense study in laboratory animal models (5). The rat has proven to be especially useful. OVX and gonadotrophin-releasing hormone agonists result in bone loss in rats, and these changes are prevented by estrogen treatment (6-9). These observations suggest similar skeletal mechanisms of action of estrogen in rats and humans. Furthermore, the skeletal changes in rats in response to partial estrogen agonists have accurately predicted the differential responses of pre-and postmenopausal women to tamoxifen treatment (10, 11).The bone loss in postmenopausal women and ovariectomized women and rats is associated with elevated bone turnover (6,(12)(13)(14). However, the bone loss is not uniform; cancellous bone is at a greater risk than cortical bone (7,14,15). In addition, there is site specificity in the loss of cancellous bone. For example, cancellous bone is lost more rapidly from the proximal tibial metaphysis than from vertebral bodies (16). Also, bone is preferenti...

show abstract

“…This is the first description of such effects of a bisphosphonate in normal animals. The strikingly larger effects on male than female animals in this study, previously reported by us [35], may be related to size/weight effects with some biomechanical impact on the skeleton [8][9][10] and/or a larger bioavailability of bisphosphonates in male compared to female rats.…”

Section: Opd Effectsmentioning

confidence: 49%

Novel experimental effects on bone material properties and the pre- and postyield behavior of bones may be independent of bone mineralization

et al. 2005

View full text Add to dashboard Cite

In this article, we summarize the results of six different tomographic/biomechanical rat studies involving hypophysectomy (Hx), ovariectomy, treatment with rhGH, olpadronate, alendronate, and toxic doses of aluminum and the development of a genetic diabetes in the eSS strain. All these conditions induced some interesting and rarely reported effects on postyield bone strength. These effects were generally related neither to the degree of mineralization or the elastic modulus of the bone tissue nor to the preyield behavior of the bones. In two particular cases (Hx, eSS), the elastic modulus of bone tissue varied independently of its degree of mineralization. These results suggest the involvement of some microstructural factor(s) of bone tissue resistance to crack progression (a postyield feature of bone behavior), rather than to crack initiation (the yield-determining factor) in the corresponding mechanism. Changes in collagen or crystal structure may play that role. These changes are relevant to the mechanism of fracture production during plastic deformation, a feature of bone strength that might be independent from mineralization. Therefore, these changes might help to explain some effects of novel treatments on bone strength unrelated to bone mineralization. This questions the belief that the remaining bone mass in metabolic osteopenias is biologically and mechanically normal.

show abstract

Determination of femur structural properties by geometric and material variables as a function of body weight in rats. Evidence of a sexual dimorphism

Cited by 45 publications

References 21 publications

Effect of maternal dexamethasone and alpha-ketoglutarate administration on skeletal development during the last three weeks of prenatal life in pigs

Effect of maternal dexamethasone and alpha-ketoglutarate administration on skeletal development during the last three weeks of prenatal life in pigs

Estrogen regulates the rate of bone turnover but bone balance in ovariectomized rats is modulated by prevailing mechanical strain

Novel experimental effects on bone material properties and the pre- and postyield behavior of bones may be independent of bone mineralization

Contact Info

Product

Resources

About