Streaming potential of human lumbar anulus fibrosus is anisotropic and affected by disc degeneration

• Published in: Journal of biomechanics Vol. 32; no. 11; pp. 1177 - 1182
• Main Authors: Gu, W.Y., Mao, X.G., Rawlins, B.A., Iatridis, J.C., Foster, R.J., Sun, D.N., Weidenbaum, M., Mow, V.C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.11.1999
• Subjects: Adolescent; Adult; Aged; Anisotropy; Anulus fibrosus; Bioelectric potentials; Biomechanics; Biomedical engineering; Cadaver; Child; Composition; Cytoplasmic Streaming; Electrokinetic properties; Electrophysiology; Humans; Intervertebral disc; Intervertebral Disc - physiopathology; Intervertebral Disc Displacement - physiopathology; Kinematics; Lumbar Vertebrae - physiopathology; Middle Aged; Nonlinear Dynamics; Soft tissue mechanics; Streaming potential; Stress, Mechanical; Weight-Bearing - physiology; Anulus fibrosus; Electrokinetic properties; Streaming potential; Soft tissue mechanics; Intervertebral disc
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/S0021-9290(99)00118-9

The streaming potential responses of non-degenerate and degenerate human anulus fibrosus were measured in a one-dimensional permeation configuration under static and dynamic loading conditions. The goal of this study was to investigate the influence of the changes in tissue structure and composition on the electrokinetic behavior of intervertebral disc tissues. It was found that the static streaming potential of the anulus fibrosus depended on the degenerative grade of the discs ( p=0.0001) and on the specimen orientation in which the fluid flows ( p=0.0001). For a statically applied pressure of 0.07 MPa, the ratio of streaming potential to applied pressure ranged from 5.3 to 6.9 mV/MPa and was largest for Grade I tissue with axial orientation and lowest for Grade III tissue with circumferential orientation. The dynamic streaming potential responses of anulus fibrosus were sensitive to the degeneration of the disc: the total harmonic distortion factor increased by 108%, from 3.92±0.66% (mean±SD) for Grade I specimens to 8.15±3.05% for Grades II and III specimens. The alteration of streaming potential reflects the changes in tissue composition and structure with degeneration. To our knowledge, this is the first reported data for the streaming potential of human intervertebral disc tissues. Knowledge of the streaming potential response of the intervertebral disc provides an understanding of potentially important signal transduction mechanisms in the disc and of the etiology of intervertebral disc degeneration.