Suture growth modulated by the oscillatory component of micromechanical strain
Suture growth modulated by the oscillatory component of micromechanical strain
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DOI：
10.1359/jbmr.2003.18.3.521
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发表时间：
2003-03-01
影响因子：
6.2
通讯作者：
Mao, JJ
中科院分区：
文献类型：
--
作者：
Kopher, RA;Mao, JJ
缝线是膜内颅面骨之间的纤维结缔组织关节。缝线由成纤维细胞组成，成纤维细胞的基质位于中心，成骨细胞位于外周，在骨骼生长过程中产生矿化基质。振荡力是否刺激缝线生长尚不清楚。在目前的工作中，我们施加静态和周期性的力量，具有相同的峰值幅度为5 N的生长兔上颌骨和量化（1）急性在体内缝骨应变反应和（2）慢性生长反应的前上颌缝（PMS）和鼻额缝（NIPS）。骨应变记录显示，在PMS和NFS中，静态力和1Hz循环力的波形均表示为相应的静态和循环缝合应变模式，平均峰值PMS应变（循环菌株为-1451 +/-137 μ mol/L，静态菌株为-1572 +/-138 μ mol/L）比平均峰值NFS菌株高约10倍（循环为124 +/-9 μ Ω，静态为134 +/-9 μ Ω）。应变极性相反：PMS为压缩，而NIPS为拉伸。然而，在体内重复施加5 N循环和静态力10分钟/天，持续12天，循环载荷诱导压缩PMS的缝合宽度（95.1 +/- 8.3 μ m）显著大于假手术对照组（69.8 +/- 8.2 μ m）和静态载荷（58.9 +/- 2.8 μ m; p < 0.01）。有趣的是，拉伸应变下的NIPS也存在相同的趋势：循环载荷（267.4 +/- 64.2 μ m）的缝合宽度显著大于假手术对照（196.0 +/- 10.1 μ m）和静态载荷（169.9 +/- 11.4 μ m）。在PMS和NIPS中，覆盖在缝线上的110 × 110 μ m网格中的细胞计数显示，与假手术对照组和静态负荷相比，重复循环负荷下的缝线细胞显著更多（p < 0.05）。新形成的缝骨的荧光标记表明，与假手术对照组和静态负荷相比，循环负荷下有更多的成骨作用。因此，周期性力的振荡分量或更准确地说，缝线中经历的所得周期性应变是缝线生长的有力刺激。在拉伸的NIPS和压缩的PMS中，通过循环机械应变增加的缝合生长表明微尺度拉伸和压缩都诱导合成代谢缝合生长反应。
Sutures are fibrous connective tissue articulations between intramembranous craniofacial bones. Sutures are composed of fibroblastic cells with their matrices in the center and osteogenic cells in the periphery producing a matrix that is mineralized during skeletal growth. Whether oscillatory forces stimulate sutural growth is unknown. In the present work, we applied static and cyclic forces with the same peak magnitude of 5N to the maxilla in growing rabbits and quantified (1) acute in vivo sutural bone strain responses and (2) chronic growth responses in the premaxillomaxillary suture (PMS) and nasofrontal suture (NIPS). Bone strain recordings showed that the waveforms of static force and 1-Hz cyclic force were expressed as corresponding static and cyclic sutural strain patterns in both the PMS and NFS, with the mean peak PMS strain (-1451 +/- 137 muepsilon for the cyclic and -1572 +/- 138 muepsilon for the static) approximately 10-fold higher than the mean peak NFS strain (124 +/- 9 muepsilon for the cyclic and 134 +/- 9 muepsilon for the static). Strain polarity was the opposite: compressive for the PMS but tensile for the NIPS. However, on application of repetitive 5N cyclic and static forces in vivo for 10 minutes/day over 12 days, cyclic loading induced significantly greater sutural widths for the compressed PMS (95.1 +/- 8.3 mum) than sham control (69.8 +/- 8.2 mum) and static loading (58.9 +/- 2.8 mum; p < 0.01). Interestingly, the same trend was true for the NIPS under tensile strain: significantly greater sutural width for cyclic loading (267.4 +/- 64.2 mu m) than sham control (196.0 +/- 10.1 mu m) and static loading (169.9 +/- 11.4 mu m). Cell counting in 110 x 110 mu m grids laid over sutures disclosed significantly more sutural cells on repetitive cyclic loading than sham control and static loading (p < 0.05) for both the PMS and NIPS. Fluorescent labeling of newly formed sutural bone demonstrated more osteogenesis on cyclic loading in comparison with sham control and static loading. Thus, the oscillatory component of cyclic force or more precisely the resulting cyclic strain experienced in sutures is a potent stimulus for sutural growth. The increased sutural growth by cyclic mechanical strain in the tensed NIPS and compressed PMS suggests that both microscale tension and compression induce anabolic sutural growth response.