Johannessen Wade, Elliott Dawn M
McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104-6081, USA.
Spine (Phila Pa 1976). 2005 Dec 15;30(24):E724-9. doi: 10.1097/01.brs.0000192236.92867.15.
The biphasic compressive material properties of normal and degenerate human nucleus pulposus tissue were measured in confined compression.
The objective of this study was to determine the effects of degeneration and age on the mechanical properties of human nucleus pulposus.
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.
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.
Degeneration produced significant decreases in swelling stress (Psw = 0.138 +/- 0.029 MPa nondegenerate, Psw = 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 (ka = 0.9 +/- 0.43 x 10(-15) m4/N-s nondegenerate, ka = 1.4 +/- 0.58 x 10(-15) m4/N-s degenerate).
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.
在受限压缩条件下测量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髓核力学性能的影响。
髓核表现出与蛋白聚糖含量成比例的肿胀行为。在剪切过程中，髓核表现出流体样和固体样特性，表明其具有双相性质。迄今为止，尚未报道人髓核的双相压缩特性。
对人髓核样本进行受限压缩测试。测量等长肿胀应力和有效聚集模量。使用线性双相理论确定组织的渗透率。将力学行为与蛋白聚糖和含水量相关联。
退变导致肿胀应力显著降低（非退变组Psw = 0.138±0.029MPa，退变组Psw = 0.037±0.038MPa）和有效聚集模量降低（非退变组H(A)(eff)=1.01±0.43MPa，退变组H(A)(eff)=0.44±0.19MPa）。这两种特性均与蛋白聚糖含量呈负相关。渗透率随退变增加（非退变组ka = 0.9±0.43×10(-15) m4/N-s，退变组ka = 1.4±0.58×10(-15) m4/N-s）。
肿胀是正常和退变髓核的主要承载机制。了解髓核的双相材料特性将有助于开发针对椎间盘退变的新治疗策略，旨在恢复椎间盘的力学功能。
