Kimmel D B, Wronski T J
Department of Medicine, Creighton University, Omaha, Nebraska 68131.
Calcif Tissue Int. 1990 Feb;46(2):101-10. doi: 10.1007/BF02556093.
One hundred ninety-eight rats were ovariectomized (OX) or sham-ovariectomized (shOX) at 100 days of age. Groups were killed at 35, 70, 100, 125, 180, 270, 360, and 540 days postsurgery. Bone mineral content (BMC) of the right femur was assayed on a dual photon absorptiometer (DPA) optimized for human spine and whole body measurements. Three regions were studied: the distal measuring 0.8 cm, the proximal measuring 0.88 cm, and the diaphysis, the remainder. The DPA technique accurately showed the ash content (r = 0.96), with a precision error of 3-5%. Whole femoral BMC was 4.3-11.1% lower in OX than shOX rats, with significant differences from 35-180 days. By 35 days, distal femoral BMC declined 6% in OX rats and rose 12% in shOX rats. Distal femoral BMC was 11.3-17.5% lower in OX than shOX rats, with significant differences at all times except 540 days. Femoral diaphyseal BMC of OX and shOX rats did not differ at any time. The relative distal femoral osteopenia which appeared by 35 days in OX rats did not worsen during the next 17 months. A DPA suited for human BMC studies is also accurate for BMC determination in bones with 250-500 mg of mineral. It is less precise for this purpose than dedicated instruments using single photon absorptiometry. However, enough precision exists to monitor the development of relative osteopenia in OX rats. Osteopenia in OX rats is confined to a region containing appreciable cancellous bone. Its self-limiting nature suggests the existence of an estrogen-dependent quantum of cancellous bone in female rats. The adult rat model is accurate for cancellous bone of the adult human, but inaccurate for cortical bone.
198只大鼠在100日龄时接受卵巢切除（OX）或假卵巢切除（shOX）手术。术后35、70、100、125、180、270、360和540天处死各实验组。使用针对人体脊柱和全身测量优化的双能光子吸收仪（DPA）测定右侧股骨的骨矿物质含量（BMC）。研究了三个区域：远端测量0.8厘米，近端测量0.88厘米，骨干为其余部分。DPA技术准确显示了灰分含量（r = 0.96），精度误差为3 - 5%。与假手术组大鼠相比，卵巢切除组大鼠的全股骨BMC低4.3 - 11.1%，在35 - 180天有显著差异。到35天时，卵巢切除组大鼠的远端股骨BMC下降了6%，假手术组大鼠则上升了12%。与假手术组大鼠相比，卵巢切除组大鼠的远端股骨BMC低11.3 - 17.5%，除540天外，在所有时间点均有显著差异。卵巢切除组和假手术组大鼠的股骨干BMC在任何时候均无差异。卵巢切除组大鼠在35天时出现的相对远端股骨骨质减少在接下来的17个月内并未恶化。适用于人体BMC研究的DPA对于矿物质含量为250 - 500毫克的骨骼中的BMC测定也很准确。为此目的，它不如使用单能光子吸收法的专用仪器精确。然而，其精度足以监测卵巢切除组大鼠相对骨质减少的发展情况。卵巢切除组大鼠的骨质减少局限于含有大量松质骨的区域。其自我限制的性质表明雌性大鼠中存在雌激素依赖的一定量松质骨。成年大鼠模型对于成年人类的松质骨是准确的，但对于皮质骨不准确。
