Alterations in trabecular bone microarchitecture in the ovine spine and distal femur following ovariectomy

Abstract

Osteoporosis is a bone disease resulting in increased fracture risk as a result of alterations in both the quantity and quality of bone. Bone quality is a combination of metabolic and microarchitectural properties of bone that can help to explain the increased susceptibility to fracture. Translational animal models are essential to understanding the pathology and evaluating potential treatments of this disease. Large animal models, such as the ovariectomized sheep, have been used as a model for post-menopausal osteoporosis. However, long-term studies have not been carried out to observe the effects of ovariectomy after more than one year. This study employed micro-computed tomography to quantify changes in microarchitectural and mechanical parameters in the femoral condyles and vertebral bodies of sheep that were sacrificed one or two years following ovariectomy. In the vertebral body, microarchitectural characteristics were significantly degraded following one year of ovariectomy in comparison to controls. The mechanical anisotropy, determined from micro-scale finite element models, was also greater in the ovariectomized groups, although the fabric tensor anisotropy was similar. There was no greater architectural degradation following two years of ovariectomy compared to one. Ovariectomy had minimal effects on the trabecular architecture of the distal femur even after two years. These results indicate that the vertebral body is the preferred anatomic site for studying bone from the ovariectomized sheep model, and that the architectural changes stabilize after the first year.

The micro-architecture of human cancellous bone from fracture neck of femur patients in relation to the structural integrity and fracture toughness of the tissue

“…In-vitro laboratory studies of utilising CT to explore the effects of microarchitecture have been made on normal and ovariectomised animal proxies (Mittra et al, 2005, Teo et al, 2006, Kreipke et al, 2014) and these explored the relationship between microarchitecture and mechanical properties of cancellous bone as well as alterations to trabecular microarchitecture following ovariectomy. There only a few studies utilising human biopsies and these suffer from low sample numbers possibly due to the difficulty of obtaining substantial amount of human osteoporotic bone material (Zhang et al, 2010, Green et al, 2011).…”

The roles of architecture and estrogen depletion in microdamage risk in trabecular bone

“…Minimal differences in architecture were seen in the femoral condyles in the ovariectomized sheep model (Kreipke et al, 2014). Because of this, the samples were not representative of osteoporotic human bone (Krug et al, 2005).…”

Uma Análise Da Oferta No Varejo Brasileiro De Produtos Oriundos De Processo De Produção Com Bem-Estar Animal

“…However, Sigrist et al (2007) reported that in sheep, 6 months after the OVX, the markers for formation and resorption returned to baseline, indicating that the model was not appropriate for human postmenopausal osteoporosis. Kreipke et al (2014) reported that OVX induces the necessary changes in bone microarchitecture for studying osteoporosis, but after a year, the changes in architecture stabilize in ovine. Chavassieux et al (2001) reported that in goats, remodelling occurred only in the cortical bone tissue regions, which was also demonstrated by increased levels of CTx one month after OVX and OC three months after OVX.…”