Department of Anatomy, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
J Biomech. 2011 Feb 3;44(3):386-90. doi: 10.1016/j.jbiomech.2010.10.023. Epub 2010 Nov 20.
While much research has been dedicated to understanding osteoporosis, the nature of mineral distribution and the mechanical property variation in diseased bone is poorly understood. The current study aimed to determine the effect of estrogen deficiency and bisphosphonate therapy on bone tissue properties using an ovine model of osteoporosis. Skeletally mature animals (4+ years) were divided into an ovariectomy group (ovx, n=20) and a non treatment control group (control, n=20). A zoledronic acid treated group was also included in which animals were estrogen deficient for 20 months prior to receiving treatment (Zol, n=4). Half of the control and ovx groups were euthanized 12 or 31 months post-operatively and all Zol animals were euthanised at 31 months. Individual trabeculae were removed from the proximal femur and were analysed at specific locations across the width of the trabeculae. The mineral content was measured using quantitative backscatter electron imaging and the modulus was measured using nanoindentation. The spatial distribution of tissue modulus and mineral content in bone from ovariectomised animals was similar to control. However, ovariectomy significantly reduced the overall mineral content and tissue modulus relative to the control group after 12 months. Interestingly, significant differences were not maintained 31 months post-OVX. Treatment with zoledronic acid increased the mineral content and tissue modulus relative to both the ovariectomised and control groups. Zoledronic acid was also found to alter the mineral and modulus gradients normally associated with healthy bone tissue. The current study provides evidence that both estrogen deficiency and zoledronic acid therapy significantly alter mineral content and the mechanical properties of trabecular tissue.
尽管已经有大量研究致力于了解骨质疏松症,但对患病骨骼中矿物质分布和力学性能变化的本质仍了解甚少。本研究旨在使用绵羊骨质疏松模型来确定雌激素缺乏和双膦酸盐治疗对骨组织特性的影响。成熟的骨骼动物(4 岁以上)分为卵巢切除术组(ovx,n=20)和非治疗对照组(control,n=20)。还包括一个唑来膦酸治疗组,其中动物在接受治疗前已经雌激素缺乏 20 个月(Zol,n=4)。对照组和 ovx 组的一半动物在手术后 12 或 31 个月被安乐死,所有 Zol 动物都在 31 个月时被安乐死。从股骨近端取出个别小梁,并在小梁宽度的特定位置进行分析。使用定量背散射电子成像测量矿物质含量,使用纳米压痕法测量模量。与对照组相比,去卵巢动物的小梁组织中矿物质含量和模量的空间分布相似。然而,与对照组相比,去卵巢 12 个月后,矿物质含量和组织模量显著降低。有趣的是,去卵巢后 31 个月,差异不再维持。与去卵巢组和对照组相比,唑来膦酸治疗增加了矿物质含量和组织模量。还发现唑来膦酸改变了与健康骨组织相关的正常矿物质和模量梯度。本研究提供的证据表明,雌激素缺乏和唑来膦酸治疗均显著改变了小梁组织的矿物质含量和力学性能。
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