Changes in intracortical microporosities induced by pharmaceutical treatment of osteoporosis as detected by high resolution micro-CT
Changes in intracortical microporosities induced by pharmaceutical treatment of osteoporosis as detected by high resolution micro-CT
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DOI：
10.1016/j.bone.2011.12.012
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发表时间：
2012-03-01
期刊：
影响因子：
4.1
通讯作者：
Judex, Stefan
中科院分区：
文献类型：
--
作者：
Tommasini, Steven M.;Trinward, Andrea;Judex, Stefan
骨的微孔隙具有重要的生物学和力学作用。在这里，我们量化了皮质骨细胞陷窝和其他小孔隙的三维变化，雌激素撤退和两种不同的骨质疏松症治疗诱导。与2D测量不同，通过基于同步辐射的mu CT收集的这些数据描述了大量多孔结构的尺寸和3D空间分布。将6个月大的雌性Sprague-Dawley大鼠分成4组，每组为年龄匹配的对照组、未处理的OVX组、用PTH处理的OVX组和用阿仑膦酸钠（ALN）处理的OVX组。在样本的骨内膜、皮质内和骨膜区域对股骨骨干内侧象限的皮质内微孔进行定量，从而可以对主要在治疗开始之前与之后形成的骨细胞陷窝进行定量。在整个厚度的内侧皮质，腔隙体积分数（LC.V/TV）是显着较低的ALN治疗的大鼠相比，PTH。在骨内膜区域，未治疗的OVX大鼠的平均骨细胞陷窝体积（< Lc.V >）显著低于年龄匹配的对照组，表明雌激素停药后骨内膜表面形成的骨细胞陷窝尺寸减小。治疗（OVX、ALN、PTH）对单位组织体积骨陷窝数量（Lc.N/TV）的影响取决于皮质内的具体位置（骨内、皮质内、骨膜）。在骨内膜和皮质内区域，Lc.N/TV在ALN中显著低于未治疗的OVX，表明ALN治疗对骨细胞陷窝密度的位点特异性影响。与ALN相比，PTH在骨内膜区域的小孔（体积为5-100 μ m（3））数量也明显更多。这种改变的微孔结构的机械影响尚不清楚，但可能有助于增强而不是恶化PTH治疗的骨强度，因为较小的骨细胞陷窝可能比较大的陷窝更能吸收剪切力。总之，这些数据表明，目前的骨质疏松症治疗可以改变皮质大鼠板层骨中微孔的数量，大小和分布。(C)2011 Elsevier Inc. All rights reserved.
Bone's microporosities play important biologic and mechanical roles. Here, we quantified 3D changes in cortical osteocyte-lacunae and other small porosities induced by estrogen withdrawal and two different osteoporosis treatments. Unlike 2D measurements, these data collected via synchrotron radiation-based mu CT describe the size and 3D spatial distribution of a large number of porous structures. Six-month old female Sprague-Dawley rats were separated into four groups of age-matched controls, untreated OVX, OVX treated with PTH, and OVX treated with Alendronate (ALN). Intracortical microporosity of the medial quadrant of the femoral diaphysis was quantified at endosteal, intracortical, and periosteal regions of the samples, allowing the quantification of osteocyte lacunae that were formed primarily before versus after the start of treatment. Across the overall thickness of the medial cortex, lacunar volume fraction (Lc.V/TV) was significantly lower in ALN treated rats compared to PTH. In the endosteal region, average osteocyte lacunar volume (< Lc.V >) of untreated OVX rats was significantly lower than in age-matched controls, indicating a decrease in osteocyte lacunar size in bone formed on the endosteal surface after estrogen withdrawal. The effect of treatment (OVX, ALN, PTH) on the number of lacunae per tissue volume (Lc.N/TV) was dependent on the specific location within the cortex (endosteal, intracortical, periosteal). In both the endosteal and intracortical regions, Lc.N/TV was significantly lower in ALN than in untreated OVX, suggesting a site-specific effect in osteocyte lacuna density with ALN treatment. There also were a significantly greater number of small pores (5-100 mu m(3) in volume) in the endosteal region for PTH compared to ALN. The mechanical impact of this altered microporosity structure is unknown, but might serve to enhance, rather than deteriorate bone strength with PTH treatment, as smaller osteocyte lacunae may be better able to absorb shear forces than larger lacunae. Together, these data demonstrate that current treatments of osteoporosis can alter the number, size, and distribution of microporosities in cortical rat lamellar bone. (C) 2011 Elsevier Inc. All rights reserved.