Frequency response of pig intervertebral disc cells subjected to dynamic hydrostatic pressure

✍ Scribed by Mehran Kasra; W. David Merryman; Kristen N. Loveless; Vijay K. Goel; James D. Martin; Joseph A. Buckwalter

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 192 KB
• Volume: 24
• Category: Article
• ISSN: 0736-0266
• DOI: 10.1002/jor.20253

✦ Synopsis

Abstract

The pathogenesis of vibration‐induced disorders of intervertebral disc at the cellular level is largely unknown. Dynamic loads with frequencies close to that of the in vivo human spine resonant frequency (4–6 Hz) have a destructive effect, which may induce extracellular disc matrix (ECM) degradation. To investigate this issue, three‐dimensional (3D) alginate cultures of normal pig intervertebral disc nucleus and inner annulus cells were tested under dynamic hydrostatic loading. Alginate cultures of each region were divided into six groups; five groups were exposed to cyclic hydrostatic pressures of frequencies 1, 3, 5, 8, and 10 Hz with the same amplitude (1 MPa), and group 6 was the control group (no loading). Cultures of different groups were loaded for 3 days (30 min daily) in a hydraulic chamber. Effects of loading frequency on disc collagen and protein metabolism were investigated by measuring ^3^H‐proline–labeled proteins associated with the cells in the extracellular matrix and release of ^3^H‐proline–labeled molecules into culture medium. The results indicated a poor synthesis rate and more degradation near the 5 Hz frequency. The repeatability of experiments was verified by performing two experiments with the same protocol. Both experiments indicated that a threshold frequency of around 5 Hz disrupted protein metabolism. © 2006 Orthopaedic Research Society. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1967–1973, 2006