Are axial intervertebral disc biomechanics determined by osmosis?

JOURNAL OF BIOMECHANICS

卷:70

Article; Proceedings Paper

Vergroesen, Pieter-Paul A.^1,2,3,4  Emanuel, Kaj S.^1,3,4  Peeters, Mirte^1,3,4  Kingma, Idsart^3,4,5  Smit, Theodoor H.^1,3,4,6 

[1] Vrije Univ Amsterdam, Med Ctr, Dept Orthoped Surg, Amsterdam, Netherlands

[2] Noord West Ziekenhuizen, Dept Orthoped Surg, Alkmaar, Netherlands

[3] MOVE Res Inst Amsterdam, Amsterdam, Netherlands

[4] Amsterdam Movement Sci Inst, Amsterdam, Netherlands

[5] Vrije Univ Amsterdam, Fac Behav & Movement Sci, Amsterdam, Netherlands

[6] Acad Med Ctr, Dept Med Biol, Amsterdam, Netherlands

关键词: Intervertebral disc;    Creep;    Osmolality;    Proteoglycans;    Permeability;   

DOI  :  10.1016/j.jbiomech.2017.04.027

来源: Elsevier

【 摘 要 】

The intervertebral disc faces high compressive forces during daily activities. Axial compression induces creeping fluid loss and reduction in disc height. With degeneration, disc fluids and height are progressively lost, altering biomechanics. It is assumed that this reduction of fluids is caused by a decline of osmolality within the disc due to proteoglycan depletion. Here we investigate the isolated effect of a reduction in osmosis on the biomechanical properties of the intervertebral disc. Continuous diurnal loading was applied to healthy caprine intervertebral discs in a loaded disc culture system for a total of 6 days. We increased testing bath osmolality with two doses of polyethylene-glycol (PEG), thereby reducing the osmotic gradient between the disc and the surrounding fluid. This way we could study the isolated effect of reduced osmosis on axial creep, without damaging the disc. We evaluated: daily creep and recovery, recovery time-constants and compressive stiffness. Additionally, we investigated water content. There was a strong dose-dependent effect of PEG concentration on water content and axial creep behaviour: disc height, amplitude and rate of creep and recovery were all significantly reduced. Axial compressive stiffness of the disc was not affected. Reduction of water content and amplitude of creep and recovery showed similarity to degenerative disc biomechanics. However, the time-constants increased, indicating that the hydraulic permeability was reduced, in contrast to what happens with degeneration. This suggests that besides the osmotic gradient, the permeability of the tissues determines healthy intervertebral disc biomechanics. (C) 2017 Published by Elsevier Ltd.

【 授权许可】

Free