Quantitative measures of femoral fracture repair in rats derived by micro-computed tomography
Quantitative measures of femoral fracture repair in rats derived by micro-computed tomography
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DOI：
10.1016/j.jbiomech.2009.01.016
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发表时间：
2009-05-11
影响因子：
2.4
通讯作者：
Gutierrez, Gloria E.
中科院分区：
文献类型：
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作者：
Nyman, Jeffry S.;Munoz, Steve;Gutierrez, Gloria E.
虽然骨折愈合经常在临床前长骨骨折模型中使用啮齿动物进行研究，但缺乏客观的定量技术来评估成功愈合。生物力学测试可能是最定量的，与成功的临床结果相关，但它是一种破坏性的技术，几乎无法深入了解与愈合相关的细胞机制。X射线计算机断层扫描（CT）的出现提供了定量和非破坏性评估骨结构和密度的机会，但尚不清楚使用该技术获得的测量结果与成功愈合的关系。为了检查可能的关系，我们使用临床前模型来测试通过显微CT（mu CT）的骨痂的定量特征与通过切除骨的三点弯曲评估的骨痂的弯曲强度、刚度和失效能量之间的统计学显著相关性。通过冲击载荷在大鼠股骨中段产生闭合的横向骨折。此后不久，大鼠接受一次性局部注射溶媒或四种剂量之一的洛伐他汀。愈合4周后处死，取出骨折股骨进行mu CT分析，然后进行三点弯曲。将感兴趣区域设置为骨折线上方和下方3.2 mm，我们获得了标准和新的mu CT衍生测量值。愈伤组织的矿化体积和矿化密度分别与愈伤组织的强度（r（xy）=-0.315，p = 0.016和r（xy）= 0.444，p < 0.0005）和硬度（r（xy）=-0.271，p = 0.040和r（xy）= 0.325，p = 0.013）呈正相关。但矿化的愈伤组织的分数和愈伤组织的惯性矩没有。该分数确实与失效能量相关（r（xy）=-0.343，p = 0.0085）。在mu CT衍生的测量中，定量愈伤组织外桥接皮质内的缺陷与愈伤组织强度产生最强的相关性（r（xy）= 0.557，p
Although fracture healing is frequently studied in pre-clinical models of long bone fractures using rodents, there is a dearth of objective quantitative techniques to assess successful healing. Biomechanical testing is possibly the most quantitative and relevant to a successful clinical outcome, but it is a destructive technique providing little insight into the cellular mechanisms associated with healing. The advent of X-ray Computed tomography (CT) has provided the opportunity to quantitatively and non-destructively assess bone structure and density, but it is unknown how measurements derived using this technology relate to successful healing. To examine possible relationships, we used a preclinical model to test for statistically significant correlations between quantitative characteristics of the callus by micro-CT (mu CT) and the bending strength, stiffness, and energy-to-failure of the callus as assessed by three-point bending of excised bones. A closed, transverse fracture was generated in the mid-shaft of rat femurs by impact loading. Shortly thereafter, the rats received a one-time, local injection of either the vehicle or one of four doses of lovastatin. Following sacrifice after 4 weeks of healing, fractured femurs were extracted for mu CT analysis and then three-point bending. Setting the region of interest to be 3.2 mm above and below the fracture line, we acquired standard and new mu CT-derived measurements. The mineralized Callus volume and the mineral density of the callus correlated positively with callus strength (r(xy) = -0.315, p = 0.016 and r(xy) = 0.444, p < 0.0005, respectively) and stiffness (r(xy) = -0.271, p = 0.040 and r(xy) = 0.325, p = 0.013, respectively), but the fraction of the callus that mineralized and the moment of inertia of the callus did not. This fraction did correlate with energy-to-failure (r(xy) = -0.343, p = 0.0085). Of the mu CT-derived measurements, quantifying defects within the outer bridging cortices of the callus produced the strongest correlation with both callus strength (r(xy) = 0.557, p