Effects of degeneration on the biphasic material properties of human nucleus pulposus in confined compression
Effects of degeneration on the biphasic material properties of human nucleus pulposus in confined compression
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DOI：
10.1097/01.brs.0000192236.92867.15
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发表时间：
2005-12-15
期刊：
影响因子：
3
通讯作者：
Elliott, DM
中科院分区：
文献类型：
--
作者：
Johannessen, W;Elliott, DM
研究设计.在有限压缩条件下测量了正常和退变的人髓核组织的双相压缩材料特性。本研究的目的是确定退变和年龄对人类髓核力学性能的影响。髓核表现出与蛋白多糖含量成比例的膨胀行为。在剪切中，核表现出流体样和固体样的性质，这表明一个两相的性质。迄今为止，人髓核的双相压缩特性尚未被证实。对人髓核样本进行了有限压缩试验。测定了等轴膨胀应力和有效骨料模量。线性双相理论用于确定组织的渗透性。力学行为与蛋白多糖和水含量相关。退化导致膨胀应力（P-sw = 0.138 +/- 0.029 MPa非退化，P-sw = 0.037 +/- 0.038 MPa退化）和有效聚集体模量（H-A（eff）= 1.01 +/- 0.43 MPa非退化，H-A（eff）= 0.44 +/- 0.19 MPa退化）显著降低。这两个属性与蛋白多糖含量呈负相关。渗透性随变性而增加（k（a）= 0.9 +/- 0.43 x 10（-15）m（4）/N-s非变性，k（a）= 1.4 +/- 0.58 x 10（-15）m（4）/ N-s变性）。肿胀是非退变和退变髓核的主要承重机制。了解髓核的双相材料特性将有助于开发旨在恢复椎间盘机械功能的椎间盘退变新治疗策略。
Study Design. The biphasic compressive material properties of normal and degenerate human nucleus pulposus tissue were measured in confined compression.Objectives. The objective of this study was to determine the effects of degeneration and age on the mechanical properties of human nucleus pulposus.Summary of Background Data. The nucleus pulposus exhibits swelling behavior in proportion to proteoglycan content. In shear, the nucleus exhibits both fluid-like and solid-like properties, suggesting a biphasic nature. To date, biphasic compressive properties of human nucleus pulpous have not been reported.Methods. Human nucleus pulposus samples were tested in confined compression. Isometric swelling stress and effective aggregate modulus were measured. Linear biphasic theory was used to determine the permeability of the tissue. Mechanical behavior was correlated with proteoglycan and water content.Results. Degeneration produced significant decreases in swelling stress (P-sw = 0.138 +/- 0.029 MPa nondegenerate, P-sw = 0.037 +/- 0.038 MPa degenerate) and effective aggregate modulus (H-A(eff) = 1.01 +/- 0.43 MPa nondegenerate, H-A(eff) = 0.44 +/- 0.19 MPa degenerate). Both properties were inversely correlated with proteoglycan content. Permeability increased with degeneration (k(a) = 0.9 +/- 0.43 x 10(-15) m(4)/N-s nondegenerate, k(a) = 1.4 +/- 0.58 x 10(-15) m(4)/ N-s degenerate).Conclusions. Swelling is the primary load-bearing mechanism in both nondegenerate and degenerate nucleus pulposus. Knowledge of the biphasic material properties of the nucleus pulposus will aid the development of new treatment strategies for disc degeneration aimed at restoring mechanical function of the intervertebral disc.