Sheep lumbar intervertebral discs as models for human discs

• Published in: Clinical biomechanics (Bristol) Vol. 17; no. 4; pp. 312 - 314
• Main Authors: Reid, J.E., Meakin, J.R., Robins, S.P., Skakle, J.M.S., Hukins, D.W.L.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2002
• Subjects: Animals; Body Water - metabolism; Collagen; Collagen - ultrastructure; Humans; Intervertebral Disc - physiology; Intervertebral Disc - ultrastructure; Intervertebral discs; Lumbar Vertebrae; Model systems; Models, Animal; Sensitivity and Specificity; Sheep; Species Specificity; Statistics, Nonparametric; Water; Water; Model systems; Intervertebral discs; Collagen
• ISSN: 0268-0033; 1879-1271
• DOI: 10.1016/S0268-0033(02)00009-8

Objective. To determine the water content, collagen content and collagen orientation angle in different regions of sheep lumbar discs. Design. A laboratory study of sheep discs obtained from an abattoir. Methods. A total of 21 sheep lumbar discs were obtained from three lumbar spines. Water content was determined by oven drying (60 °C) to constant mass. Collagen content was determined by hydroxyproline analysis. Fibre orientation angles were determined by X-ray diffraction. Results. Water content increased from 74% of total tissue mass in the outer annulus, to 82% in the inner annulus, to 86% in the nucleus. Collagen content decreased from 30% of total tissue mass in the outer region to 20% in the inner region of the anterior and lateral annulus; it was 16% in the posterior annulus. The orientation angle of the collagen fibres decreased from 59° in the outer region to 56° in the inner region of the anterior and lateral annulus; it was 51° in the posterior annulus. Conclusions. Sheep lumbar intervertebral discs provide a reasonable model for human lumbar intervertebral discs. Relevance Sheep lumbar discs have been used to investigate the effects of removing and replacing the nucleus. These studies indicate that removal of nucleus may lead to further disc degeneration and indicate the material properties required for an implant material. The relevance of these previous studies is increased if human and sheep lumbar discs have a similar composition and structure.