Trabecular bone in the bird knee responds with high sensitivity to changes in load orientation
Trabecular bone in the bird knee responds with high sensitivity to changes in load orientation
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DOI：
10.1242/jeb.01971
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发表时间：
2006-01-01
影响因子：
2.8
通讯作者：
Cooper, DML
中科院分区：
文献类型：
--
作者：
Pontzer, H;Lieberman, DE;Cooper, DML
沃尔夫轨迹定向定律提出小梁支柱与关节内主要压缩载荷的方向对齐。尽管沃尔夫定律在骨骼生物学中被广泛考虑，但在控制个体发育阶段、活动水平和物种差异（所有可能影响骨小梁生长的因素）时从未经过实验测试。在这里，我们报告了对沃尔夫定律的实验测试，该实验使用物种内设计，在年龄匹配的受试者中进行生理正常水平的骨应变。两组年龄匹配的珍珠鸡 Numida meleagris 幼年在 0 度（水平组）或 20 度（倾斜组）的跑步机上跑步，在 45 天的治疗期内每天跑步 10 分钟。在 20 度倾斜跑步机上跑步的鸟儿在中间站立（地面反作用力峰值点）时使用比水平组更弯曲的膝盖。关节姿势的这种差异使我们能够测试小梁排列对膝关节负载方向改变的敏感性。使用一种新的基于氡变换的方法来测量小梁方向，我们的分析表明股骨远端的细小梁骨在关节角度的变化和小梁方向之间具有高度的对应性。这种响应的敏感性支持了骨小梁动态适应峰值压缩力方向的预测。
Wolff's law of trajectorial orientation proposes that trabecular struts align with the orientation of dominant compressive loads within a joint. Although widely considered in skeletal biology, Wolff's law has never been experimentally tested while controlling for ontogenetic stage, activity level, and species differences, all factors that may affect trabecular bone growth. Here we report an experimental test of Wolff's law using a within-species design in age-matched subjects experiencing physiologically normal levels of bone strain. Two age-matched groups of juvenile guinea fowl Numida meleagris ran on a treadmill set at either 0 degrees (Level group) or 20 degrees (Incline group), for 10 min per day over a 45-day treatment period. Birds running on the 20 degrees inclined treadmill used more-flexed knees than those in the Level group at midstance (the point of peak ground reaction force). This difference in joint posture enabled us to test the sensitivity of trabecular alignment to altered load orientation in the knee. Using a new radon transform-based method for measuring trabecular orientation, our analysis shows that the fine trabecular bone in the distal femur has a high degree of correspondence between changes in joint angle and trabecular orientation. The sensitivity of this response supports the prediction that trabecular bone adapts dynamically to the orientation of peak compressive forces.