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Region specific response of intervertebral disc cells to complex dynamic loading: an organ culture study using a dynamic torsion-compression bioreactor.

Chan SC, Walser J, Käppeli P, Shamsollahi MJ, Ferguson SJ, Gantenbein-Ritter B - PLoS ONE (2013)

Bottom Line: Our results provided strong evidence that complex loading induced a stronger degree of disc degeneration compared to one degree of freedom loading.Cell apoptotic activity and glycosaminoglycan content were also quantified but there were no statistically significant differences found.Our results stress the importance of complex loading on the initiation and progression of disc degeneration.

View Article: PubMed Central - PubMed

Affiliation: Tissue and Organ Mechanobiology group, Institute for Surgical Technology & Biomechanics, University of Bern, Bern, Switzerland.

ABSTRACT
The spine is routinely subjected to repetitive complex loading consisting of axial compression, torsion, flexion and extension. Mechanical loading is one of the important causes of spinal diseases, including disc herniation and disc degeneration. It is known that static and dynamic compression can lead to progressive disc degeneration, but little is known about the mechanobiology of the disc subjected to combined dynamic compression and torsion. Therefore, the purpose of this study was to compare the mechanobiology of the intervertebral disc when subjected to combined dynamic compression and axial torsion or pure dynamic compression or axial torsion using organ culture. We applied four different loading modalities [1. control: no loading (NL), 2. cyclic compression (CC), 3. cyclic torsion (CT), and 4. combined cyclic compression and torsion (CCT)] on bovine caudal disc explants using our custom made dynamic loading bioreactor for disc organ culture. Loads were applied for 8 h/day and continued for 14 days, all at a physiological magnitude and frequency. Our results provided strong evidence that complex loading induced a stronger degree of disc degeneration compared to one degree of freedom loading. In the CCT group, less than 10% nucleus pulposus (NP) cells survived the 14 days of loading, while cell viabilities were maintained above 70% in the NP of all the other three groups and in the annulus fibrosus (AF) of all the groups. Gene expression analysis revealed a strong up-regulation in matrix genes and matrix remodeling genes in the AF of the CCT group. Cell apoptotic activity and glycosaminoglycan content were also quantified but there were no statistically significant differences found. Cell morphology in the NP of the CCT was changed, as shown by histological evaluation. Our results stress the importance of complex loading on the initiation and progression of disc degeneration.

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Related in: MedlinePlus

Histological analysis showing morphology of cells in the transition zone of the endplate and the nucleus pulposus.MMA sections were stained with safranin O/fast green. Cells in the transition zone between the cartilaginous endplates (EP) and nucleus pulposus (NP) (separated by dotted black line) stayed as rounded chondrocyte-like cells (indicated by black arrows) as in hyaline cartilage in CC and CT groups. Some cells in the cartilaginous endplates of the CCT group stayed as chondrocyte-like cells whereas cells right after the endplates zone changed to cells with spindle-shaped nucleus and cell lacunae were lost (indicated by yellow circles). CC: cyclic compression, CT: cyclic torsion, CCT: combined compression torsion. N = 2.
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pone-0072489-g009: Histological analysis showing morphology of cells in the transition zone of the endplate and the nucleus pulposus.MMA sections were stained with safranin O/fast green. Cells in the transition zone between the cartilaginous endplates (EP) and nucleus pulposus (NP) (separated by dotted black line) stayed as rounded chondrocyte-like cells (indicated by black arrows) as in hyaline cartilage in CC and CT groups. Some cells in the cartilaginous endplates of the CCT group stayed as chondrocyte-like cells whereas cells right after the endplates zone changed to cells with spindle-shaped nucleus and cell lacunae were lost (indicated by yellow circles). CC: cyclic compression, CT: cyclic torsion, CCT: combined compression torsion. N = 2.

Mentions: Histological sections were stained with safranin O & fast green to show the morphology of the cells and the overall matrix organization. No significant changes in matrix organization between different groups could be observed (data not shown). In the transition zone between the cartilaginous endplates (EP) and the nucleus pulposus (NP) (Figure 9, EP/NP border indicated by dotted black line), cells stayed as chondrocyte-like cells (indicated by black arrows) in the CC and CT groups with a round cell nucleus surrounded by lacunae. However, in CCT, very few cells stayed as chondrocyte-like cells (indicated by black arrows) in the cartilaginous endplate and cells right across the endplate region changed to spindle-shaped (indicated by a yellow circle) and the cell lacunae and the cell boundary were lost.


Region specific response of intervertebral disc cells to complex dynamic loading: an organ culture study using a dynamic torsion-compression bioreactor.

Chan SC, Walser J, Käppeli P, Shamsollahi MJ, Ferguson SJ, Gantenbein-Ritter B - PLoS ONE (2013)

Histological analysis showing morphology of cells in the transition zone of the endplate and the nucleus pulposus.MMA sections were stained with safranin O/fast green. Cells in the transition zone between the cartilaginous endplates (EP) and nucleus pulposus (NP) (separated by dotted black line) stayed as rounded chondrocyte-like cells (indicated by black arrows) as in hyaline cartilage in CC and CT groups. Some cells in the cartilaginous endplates of the CCT group stayed as chondrocyte-like cells whereas cells right after the endplates zone changed to cells with spindle-shaped nucleus and cell lacunae were lost (indicated by yellow circles). CC: cyclic compression, CT: cyclic torsion, CCT: combined compression torsion. N = 2.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3755972&req=5

pone-0072489-g009: Histological analysis showing morphology of cells in the transition zone of the endplate and the nucleus pulposus.MMA sections were stained with safranin O/fast green. Cells in the transition zone between the cartilaginous endplates (EP) and nucleus pulposus (NP) (separated by dotted black line) stayed as rounded chondrocyte-like cells (indicated by black arrows) as in hyaline cartilage in CC and CT groups. Some cells in the cartilaginous endplates of the CCT group stayed as chondrocyte-like cells whereas cells right after the endplates zone changed to cells with spindle-shaped nucleus and cell lacunae were lost (indicated by yellow circles). CC: cyclic compression, CT: cyclic torsion, CCT: combined compression torsion. N = 2.
Mentions: Histological sections were stained with safranin O & fast green to show the morphology of the cells and the overall matrix organization. No significant changes in matrix organization between different groups could be observed (data not shown). In the transition zone between the cartilaginous endplates (EP) and the nucleus pulposus (NP) (Figure 9, EP/NP border indicated by dotted black line), cells stayed as chondrocyte-like cells (indicated by black arrows) in the CC and CT groups with a round cell nucleus surrounded by lacunae. However, in CCT, very few cells stayed as chondrocyte-like cells (indicated by black arrows) in the cartilaginous endplate and cells right across the endplate region changed to spindle-shaped (indicated by a yellow circle) and the cell lacunae and the cell boundary were lost.

Bottom Line: Our results provided strong evidence that complex loading induced a stronger degree of disc degeneration compared to one degree of freedom loading.Cell apoptotic activity and glycosaminoglycan content were also quantified but there were no statistically significant differences found.Our results stress the importance of complex loading on the initiation and progression of disc degeneration.

View Article: PubMed Central - PubMed

Affiliation: Tissue and Organ Mechanobiology group, Institute for Surgical Technology & Biomechanics, University of Bern, Bern, Switzerland.

ABSTRACT
The spine is routinely subjected to repetitive complex loading consisting of axial compression, torsion, flexion and extension. Mechanical loading is one of the important causes of spinal diseases, including disc herniation and disc degeneration. It is known that static and dynamic compression can lead to progressive disc degeneration, but little is known about the mechanobiology of the disc subjected to combined dynamic compression and torsion. Therefore, the purpose of this study was to compare the mechanobiology of the intervertebral disc when subjected to combined dynamic compression and axial torsion or pure dynamic compression or axial torsion using organ culture. We applied four different loading modalities [1. control: no loading (NL), 2. cyclic compression (CC), 3. cyclic torsion (CT), and 4. combined cyclic compression and torsion (CCT)] on bovine caudal disc explants using our custom made dynamic loading bioreactor for disc organ culture. Loads were applied for 8 h/day and continued for 14 days, all at a physiological magnitude and frequency. Our results provided strong evidence that complex loading induced a stronger degree of disc degeneration compared to one degree of freedom loading. In the CCT group, less than 10% nucleus pulposus (NP) cells survived the 14 days of loading, while cell viabilities were maintained above 70% in the NP of all the other three groups and in the annulus fibrosus (AF) of all the groups. Gene expression analysis revealed a strong up-regulation in matrix genes and matrix remodeling genes in the AF of the CCT group. Cell apoptotic activity and glycosaminoglycan content were also quantified but there were no statistically significant differences found. Cell morphology in the NP of the CCT was changed, as shown by histological evaluation. Our results stress the importance of complex loading on the initiation and progression of disc degeneration.

Show MeSH
Related in: MedlinePlus