A comparison between porcine, ovine, and bovine intervertebral disc anatomy and single lamella annulus fibrosus tensile properties

Abstract

This project aimed to compare gross anatomical measures and biomechanical properties of single lamellae from the annulus fibrosus of ovine and porcine lumbar vertebrae, and bovine tail vertebrae. The morphology of the vertebrae of these species differ significantly both from each other and from human, yet how these differences alter biomechanical properties is unknown. Geometric parameters measured in this study included: 1) absolute and relative intervertebral (IVD) and vertebral body height and 2) absolute and relative intervertebral disc (IVD) anterior-posterior (AP) and medial-lateral (ML) widths. Single lamella tensile properties included toe-region stress and stretch ratio, stiffness, and tensile strength. As expected, the bovine tail IVD revealed a more circular shape compared with both the ovine and porcine lumbar IVD. The bovine tail also had the largest IVD to vertebral body height ratio (due to having the highest absolute IVD height). Bovine tail lamellae were also found to be strongest and stiffest (in tension) while ovine lumbar lamellae were weakest and most compliant. Histological analysis revealed the greatest proportion of collagen in the bovine corroborating findings of increased strength and stiffness. The observed differences in anatomical shape, connective tissue composition, and tensile properties need to be considered when choosing an appropriate model for IVD research.

Lamellar and fibre bundle mechanics of the annulus fibrosus in bovine intervertebral disc

“…For instance, uni-and bi-axial tests have been used to determine the stressstrain response of the annulus [10,11], down to the level of single lamella [12,13]. Most previous work has, however, inferred the mechanical behaviour of the tissue by tracking cells [14,15] or markers that were glued or photobleached on the tissue [10,[14][15][16], or alternatively relied on relatively low resolution tissue tracking (for instance, 0.2 mm 2 elements [16,17]).…”

Degenerative lumbar disc disease: in vivo data support the rationale for the selection of appropriate animal models

“…Compared to humans, rabbits have the most elliptical discs, with a smaller dorsoventral length/lateral length ratio (O'Connell et al, 2007). Bovine tail IVDs are more rounded (Monaco et al, 2016) and their NP is more central. The cow tail IVD is one of the thickest and its NP area normalised to the total disc area is one of the closest to humans (O'Connell et al, 2007).…”

“…These modifications alter the biomechanical properties of the whole IVD. The lesions extend from the lumbar IVD to the tail and affect around 50 % of the animals by the age of 18 months (Moskowitz et al, 1990). DDD in the sand rat is also generally associated with diffuse idiopathic skeletal hyperostosis and radiographic signs of bony degeneration (facet changes, wedging, end plate spurring and calcification).…”

“…Kyphoscoliosis is due to malformations of vertebral bodies caused by failure of vertebral ossification centres to form and/or to fuse properly during embryonic or foetal development. Adler et al, 1983Moskowitz et al, 1990Silberberg, 1988et al, Ziv et al, 1992 Inherited It induces spinal deformity that leads to dorsal (kyphosis) and lateral (scoliosis) curvature. In mice, the kyphoscoliosis peptidase gene (ky) has been identified.…”

“…Intuitively, spontaneous models of DDD seem particularly relevant because of their similarity to human degenerative disease. Moreover, they have been described in a wide variety of species from sand rats (Gruber et al, 2002;Gruber et al, 2006;Moskowitz et al, 1990;Pokharna et al, 1994;Tapp et al, 2008;Ziv et al, 1992) to non-human primates (Lauerman et al, 1992;Nuckley et al, 2008;Platenberg et al, 2001), as well as rabbits (Clouet et al, 2011;Leung et al, 2008), dogs (Bergknut et al, 2011;Bergknut et al, 2012;Brisson, 2010;Cherrone et al, 2004;Griffin et al, 2009;Priester, 1976) and sheep (Nisolle et al, 2016). Consequently, these models, which include species of different sizes, are compatible with a broad range of experimental protocols, notably those designed to evaluate surgical procedures related to regenerative strategies with injections into the NP.…”