Risedronate preserves trabecular architecture and increases bone strength in vertebra of ovariectomized minipigs as measured by three-dimensional microcomputed tomography
Risedronate preserves trabecular architecture and increases bone strength in vertebra of ovariectomized minipigs as measured by three-dimensional microcomputed tomography
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DOI：
10.1359/jbmr.2002.17.7.1139
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发表时间：
2002-07-01
影响因子：
6.2
通讯作者：
Phipps, RJ
中科院分区：
文献类型：
--
作者：
Borah, B;Dufresne, TE;Phipps, RJ
利塞膦酸钠可降低骨质疏松症患者在治疗1年内新发椎骨骨折的风险高达70%。认为骨量增加和骨结构保留均有助于抗骨折作用。我们的目的是确定利塞膦酸钠对骨小梁质量和结构的影响，并确定质量和结构对去卵巢（OVX）小型猪椎骨强度的相对贡献。小型猪在18月龄时进行OVX，并以0.5 mg/kg/天或2.5 mg/kg/天的剂量每天用溶剂或利塞膦酸钠治疗18个月。通过3D显微计算机断层扫描（muCT）评价Sinclair S1小型猪L4椎体核心的三维（3D）骨结构。与OVX对照组相比，两个治疗组的椎体骨体积（骨体积/组织体积[BV/TV]）均较高（p < 0.05）。在2.5 mg/kg剂量下，结构变化更显著，并且与中段相比，在头尾端更普遍。在较高剂量下，骨小梁厚度（Tb.Th）、骨小梁数量（Tb.N）和连接性较高，而骨髓星星体积（Ma.St.V）和骨小梁分离（Tb.Sp）较低（p < 0.05）。小梁分离变异指数（TSVI），一种新的结构变异近似测量，在2.5 mg/kg治疗组中较小（p < 0.05）。在该组中，通过各向异性程度（DA）的降低和交叉支柱百分比（%交叉支柱; p < 0.05）的增加证实了与头尾轴正交的小梁的显著保留。与OVX组相比，2.5 mg/kg利塞膦酸钠组的标准化最大负荷（强度）和标准化刚度均高于OVX组（p < 0.05）。BV/TV单独可以解释76%的骨强度变异。骨体积和结构变量的组合解释了>90%的强度。研究表明，利塞膦酸钠保留了OVX小型猪椎骨中的骨小梁结构，并且骨强度与骨量和结构紧密相关。
Risedronate reduces the risk of new vertebral fractures up to 70% within I year of treatment in patients with osteoporosis. Both increases in bone mass and preservation of bone architecture are thought to contribute to antifracture effects. Our objectives were to determine the effects of risedronate on trabecular bone mass and architecture and to determine the relative contributions of mass and architecture to strength in the vertebra of ovariectomized (OVX) minipigs. The minipigs were OVX at 18 months of age and were treated daily for 18 months with either vehicle or risedronate at doses of 0.5 mg/kg per day or 2.5 mg/kg per day. The three-dimensional (3D) bone architecture of the L4 vertebral cores of Sinclair S1 minipigs was evaluated by 3D microcomputed tomography (muCT). Compared with the OVX control, the vertebral bone volume (bone volume/tissue volume [BV/TV]) was higher in both treated groups (p < 0.05). The architectural changes were more significant at the 2.5-mg/kg dose and were more prevalent at the cranial-caudal ends compared with the midsection. At the higher dose, the trabecular thickness (Tb.Th), trabecular number (Tb.N), and connectivity were higher, and marrow star volume (Ma.St.V) and trabecular separation (Tb.Sp) were lower (p < 0.05). The trabecular separation variation index (TSVI), a new measure to approximate structural variations, was smaller in the 2.5-mg/kg-treated group (p < 0.05). In this group, a significant preservation of trabeculae orthogonal to the cranial-caudal axis was confirmed by a decrease in the degree of anisotropy (DA) and an increase in the percent Cross-strut (%Cross-strut; p < 0.05). Both normalized maximum load (strength) and normalized stiffness of the same vertebral cores were higher in the 2.5-mg/kg risedronate group compared with the OVX group (p < 0.05). BV/TV alone could explain 76% of the variability of the bone strength. The combination of bone volume and architectural variables explained >90% of the strength. The study showed that risedronate preserved trabecular architecture in the vertebra of OVX minipigs, and that bone strength is tightly coupled to bone mass and architecture.