This study investigates the changes due to crosslinking treatment in stiffness,
permeability, and glycosaminoglycan (GAG) content of bovine intervertebral discs.
The objective of this study was to determine the mechanical and biochemical
effects of crosslinking treatment on lumbar bovine tissue.
Previous studies have found that crosslinking can increase stiffness and
permeability in the intervertebral disc. These changes have not yet been investigated by
confined compression, stress-relaxation tests of young bovine tissue.
Eleven lumbar motion segments were harvested from calf spines and soaked in a
saline solution or one of four crosslinking treatments (genipin, methylglyoxal,
proanthrocyanidin, and EDC). Five mm diameter samples were removed from the midannulus
region at anterior / anterior-lateral locations, confined in a saline bath, swelled to
equilibrium, and tested in confined compression stress-relaxation to 15% strain in 5%
increments. Radial samples were also harvested, treated with saline solution and EDC,
and tested in the same manner. The aggregate modulus and hydraulic permeability were
calculated using the nonlinear biphasic theory. Swelling pressure was calculated as the load at swelling equilibrium. GAG content was measured using the dimethylmethylene
blue assay. Differences with P value < 0.05 were considered significant.
In the axial orientation, all crosslinking treatments except methyglyoxal at least
doubled the aggregate modulus relative to soaked controls (P less than 0.05). Genipin treatment
resulted in 78% lower axial permeability, proanthrocyanidin (PA) 50% lower, and EDC
treatment 84% lower relative to soaked controls (P < 0.05). GAG content measured in
the methyglyoxal treatment group was 25% lower than in soaked control group. Genipin
(G), proanthrocyanidin (PA), and EDC treatment increased the swelling pressure by at
least 65% (P less than 0.05). In the radial orientation, EDC treatment increased the stiffness by
75%, and did not significantly affect the permeability or swelling pressure.
Some crosslinking treatments proved effective in increasing the stiffness and
swelling pressure of the disc. The increased swelling pressure in G, PA, and EDC
treatment groups relative to soaked controls suggests reduced GAG leaching during
soaking treatment, further confirmed by the reduction in permeability in these groups.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2009-05-720 |
| Date | 2009 May 1900 |
| Creators | Golightly, Jonathan M. |
| Contributors | Hedman, Thomas P. |
| Source Sets | Texas A and M University |
| Language | English |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | application/pdf |
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