Quantity and quality of trabecular bone in the femur are enhanced by a strongly anabolic, noninvasive mechanical intervention
Quantity and quality of trabecular bone in the femur are enhanced by a strongly anabolic, noninvasive mechanical intervention
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DOI：
10.1359/jbmr.2002.17.2.349
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发表时间：
2002-02-01
影响因子：
6.2
通讯作者：
Qin, YX
中科院分区：
文献类型：
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作者：
Rubin, C;Turner, AS;Qin, YX
骨骼对机械刺激的敏感性是骨量和形态的关键决定因素。我们已经提出了极低的水平(2000微应变)。如果这些低水平的菌株确实是合成代谢的，那么这种敏感性可以作为基于生物力学的骨质疏松症干预的基础。为了验证这一假设，成年雌性绵羊的后肢被刺激20分钟，每天使用0.3g的非侵入性垂直振荡，足以在胫骨皮质上诱导大约5微应变。刺激1年后，取实验动物股骨远端10 mm大小的骨小梁(n=8)，与对照组(n=9)进行物理性能比较，并进行微CT扫描和材料测试。骨矿含量(BMC)增加10.6%(p<；0.05)，骨小梁数量(Tb.N)增加8.3%(p<；0.01)，骨小梁间距减少11.3%(p<；0.01)，表明新骨小梁的生成和现有骨小梁的增厚均增加了骨量。骨小梁形态因子(TBPf)下降24.2%(p<；0.03)，表明骨小梁形态由棒状向板状转变。纵向的刚度和强度显著增加(分别为12.1%和26.7%；P<；0.05)，表明适应主要发生在承重平面。这些结果表明，极低水平的机械刺激可以改善松质骨的数量和质量。这些变形比剧烈运动时产生的峰值应变低几个数量级，表明这种基于生物力学的信号可能成为治疗骨质疏松症的有效干预手段。
The skeleton's sensitivity to mechanical stimuli represents a critical determinant of bone mass and morphology. We have proposed that the extremely low level (2000 microstrain). If these low-level strains are indeed anabolic, then this sensitivity could serve as the basis for a biomechanically based intervention for osteoporosis. To evaluate this hypothesis, the hindlimbs of adult female sheep were stimulated for 20 minutes/day using a noninvasive 0.3g vertical oscillation sufficient to induce approximately 5 microstrain on the cortex of the tibia. After 1 year of stimulation, the physical properties of 10-mm cubes of trabecular bone from the distal femoral condyle of experimental animals (n = 8) were compared with controls (it = 9), as evaluated using microcomputed tomography (muCT) scanning and materials testing. Bone mineral content (BMC) was 10.6% greater (p < 0.05), and the trabecular number (Tb.N) was 8.3% higher in the experimental animals (p < 0.01), and trabecular spacing decreased by 11.3% (p < 0.01), indicating that bone quantity was increased both by the creation of new trabeculae and the thickening of existing trabeculae. The trabecular bone pattern factor (TBPf) decreased 24.2% (p < 0.03), indicating trabecular morphology adapting from rod shape to plate shape. Significant increases in stiffness and strength were observed in the longitudinal direction (12.1 % and 26.7%, respectively; both,p < 0.05), indicating that the adaptation occurred primarily in the plane of weightbearing. These results show that extremely low level mechanical stimuli improve both the quantity and the quality of trabecular bone. That these deformations are several orders of magnitude below those peak strains which arise during vigorous activity indicates that this biomechanically based signal may serve as an effective intervention for osteoporosis.