Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
J Orthop Res. 2013 Nov;31(11):1708-12. doi: 10.1002/jor.22424. Epub 2013 Jul 6.
We investigated the effects of stress-shielding on both viscoelastic properties and microstructure of collagen fibers in the Achilles tendon by proton double-quantum filtered ((1) H-DQF) NMR spectroscopy. The right hind-limbs of 20 Japanese white rabbits were immobilized for 4 weeks in a cast with the ankle in plantarflexion. Dynamic viscoelasticity of the Achilles tendons was measured using a viscoelastic spectrometer. Proton DQF NMR signals were analyzed to determine the residual dipolar coupling of bound water molecules in the Achilles tendons. Both the dynamic storage modulus (E') and dynamic loss modulus (E″) decreased significantly in the Achilles tendons of the stress-shielding group. The results of the (1) H-DQF NMR examination demonstrated significantly reduced residual dipolar coupling in the Achilles tendons of this same group. The disorientation of collagen fibers by stress-shielding should contribute to degradation of the dynamic storage and loss moduli. The alterations of the collagen fiber orientation that contributed to the function of tendinous tissue can be evaluated by performing an analysis of (1) H DQF NMR spectroscopy.
我们通过质子双量子过滤（1 H-DQF）NMR 光谱研究了在跟腱中应力屏蔽对粘弹性性质和胶原纤维微观结构的影响。20 只日本白兔的右后肢在跖屈位的石膏中固定 4 周。使用粘弹性光谱仪测量跟腱的动态粘弹性。分析质子 DQF NMR 信号以确定跟腱中结合水的剩余偶极耦合。在应力屏蔽组中，跟腱的动态储能模量（E'）和动态损耗模量（E"）均显著降低。1 H-DQF NMR 检查的结果表明，同一组的跟腱中剩余偶极耦合显著降低。由应力屏蔽引起的胶原纤维的取向错乱可能导致动态储能和损耗模量的降解。通过进行 1 H-DQF NMR 光谱分析，可以评估胶原纤维取向的改变，这些改变与腱组织的功能有关。
