TY - JOUR
T1 - Changes in intervertebral disk mechanical behavior during early degeneration
AU - Paul, Cornelis P.L.
AU - Emanuel, Kaj S.
AU - Kingma, Idsart
AU - Van Der Veen, Albert J.
AU - Holewijn, Roderick M.
AU - Vergroesen, Pieter Paul A.
AU - Van De Ven, Peter M.
AU - Mullender, Margriet G.
AU - Helder, Marco N.
AU - Smit, Theodoor H.
PY - 2018/9/1
Y1 - 2018/9/1
N2 - Intervertebral disk (IVD) degeneration is commonly described by loss of height and hydration. However, in the first stage of IVD degeneration, this loss has not yet occurred. In the current study, we use an ex vivo degeneration model to analyze the changes in IVDs mechanical behavior in the first phase of degeneration. We characterize these changes by stretched-exponential fitting, and suggest the fitted parameters as markers for early degeneration. Enzymatic degeneration of healthy lumbar caprine IVDs was induced by injecting 100 μL of Chondroïtinase ABC (Cabc) into the nucleus. A no-intervention and phosphate buffered saline (PBS) injected group were used as controls. IVDs were cultured in a bioreactor for 20 days under diurnal, simulated-physiological loading (SPL) conditions. Disk deformation was continuously monitored. Changes in disk height recovery behavior were quantified using stretched-exponential fitting. Disk height, histological sections, and water- and glycosaminoglycan (GAG)-content measurements were used as gold standards for the degenerative state. Cabc injection caused significant GAG loss from the nucleus and had detrimental effects on poro-elastic mechanical properties of the IVDs. These were progressive over time, with a propensity toward more linear recovery behavior. On histological sections, both PBS and Cabc injected IVDs showed moderate degeneration. A small GAG loss yields changes in IVD recovery behavior, which can be quantified with stretched-exponential fitting. Parameters changed significantly compared to control. Studies on disk degeneration and biomaterial engineering for degenerative disk disease (DDD) could benefit from focusing on IVD biomechanical behavior rather than height and water-content, as a marker for early disk degeneration.
AB - Intervertebral disk (IVD) degeneration is commonly described by loss of height and hydration. However, in the first stage of IVD degeneration, this loss has not yet occurred. In the current study, we use an ex vivo degeneration model to analyze the changes in IVDs mechanical behavior in the first phase of degeneration. We characterize these changes by stretched-exponential fitting, and suggest the fitted parameters as markers for early degeneration. Enzymatic degeneration of healthy lumbar caprine IVDs was induced by injecting 100 μL of Chondroïtinase ABC (Cabc) into the nucleus. A no-intervention and phosphate buffered saline (PBS) injected group were used as controls. IVDs were cultured in a bioreactor for 20 days under diurnal, simulated-physiological loading (SPL) conditions. Disk deformation was continuously monitored. Changes in disk height recovery behavior were quantified using stretched-exponential fitting. Disk height, histological sections, and water- and glycosaminoglycan (GAG)-content measurements were used as gold standards for the degenerative state. Cabc injection caused significant GAG loss from the nucleus and had detrimental effects on poro-elastic mechanical properties of the IVDs. These were progressive over time, with a propensity toward more linear recovery behavior. On histological sections, both PBS and Cabc injected IVDs showed moderate degeneration. A small GAG loss yields changes in IVD recovery behavior, which can be quantified with stretched-exponential fitting. Parameters changed significantly compared to control. Studies on disk degeneration and biomaterial engineering for degenerative disk disease (DDD) could benefit from focusing on IVD biomechanical behavior rather than height and water-content, as a marker for early disk degeneration.
KW - GAG
KW - IVD
KW - biomechanical
KW - bioreactor
KW - caprine
KW - degeneration
KW - glycosaminoglycans
KW - intervertebral disk
KW - lumbar
KW - puncture
KW - spine
KW - stretched-exponential fitting
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UR - https://www.ncbi.nlm.nih.gov/pubmed/29801164
U2 - https://doi.org/10.1115/1.4039890
DO - https://doi.org/10.1115/1.4039890
M3 - Article
C2 - 29801164
SN - 0148-0731
VL - 140
SP - 1
EP - 9
JO - Journal of biomechanical engineering
JF - Journal of biomechanical engineering
IS - 9
M1 - 091008
ER -