TY - JOUR
T1 - Combined enzymatic degradation of proteoglycans and collagen significantly alters intratissue strains in articular cartilage during cyclic compression
AU - Pastrama, Maria Ioana
AU - Ortiz, Ana Caxaido
AU - Zevenbergen, Lianne
AU - Famaey, Nele
AU - Gsell, Willy
AU - Neu, Corey P.
AU - Himmelreich, Uwe
AU - Jonkers, Ilse
PY - 2019/10/1
Y1 - 2019/10/1
N2 - As degenerative joint diseases such as osteoarthritis (OA) progress, the matrix constituents, particularly collagen fibrils and proteoglycans, become damaged, therefore deteriorating the tissue's mechanical properties. This study aims to further the understanding of the effect of degradation of the different cartilage constituents on the mechanical loading environment in early stage OA. To this end, intact, collagen- and proteoglycan-depleted cartilage plugs were cyclically loaded in axial compression using an experimental model simulating in vivo cartilage-on-cartilage contact conditions in a micro-MRI scanner. Depletion of collagen and proteoglycans was achieved through enzymatic degradation with collagenase and chondroitinase ABC, respectively. Using a displacement-encoded imaging sequence (DENSE), strains were computed and compared in intact and degraded samples. The results revealed that, while degradation with one or the other enzyme had little effect on the contact strains, degradation with a combination of both enzymes caused an increase in the means and variance of the transverse, axial and shear strains, particularly in the superficial zone of the cartilage. This effect indicates that the balance between cartilage matrix constituents plays an essential role in maintaining the mechanical properties of the tissue, and a disturbance in this balance leads to a decrease of the load bearing capacity associated with degenerative joint diseases such as OA.
AB - As degenerative joint diseases such as osteoarthritis (OA) progress, the matrix constituents, particularly collagen fibrils and proteoglycans, become damaged, therefore deteriorating the tissue's mechanical properties. This study aims to further the understanding of the effect of degradation of the different cartilage constituents on the mechanical loading environment in early stage OA. To this end, intact, collagen- and proteoglycan-depleted cartilage plugs were cyclically loaded in axial compression using an experimental model simulating in vivo cartilage-on-cartilage contact conditions in a micro-MRI scanner. Depletion of collagen and proteoglycans was achieved through enzymatic degradation with collagenase and chondroitinase ABC, respectively. Using a displacement-encoded imaging sequence (DENSE), strains were computed and compared in intact and degraded samples. The results revealed that, while degradation with one or the other enzyme had little effect on the contact strains, degradation with a combination of both enzymes caused an increase in the means and variance of the transverse, axial and shear strains, particularly in the superficial zone of the cartilage. This effect indicates that the balance between cartilage matrix constituents plays an essential role in maintaining the mechanical properties of the tissue, and a disturbance in this balance leads to a decrease of the load bearing capacity associated with degenerative joint diseases such as OA.
KW - Articular cartilage
KW - Displacement-encoded micro-MRI
KW - Dynamic compression
KW - Enzymatic degradation
KW - Strain analysis
UR - http://www.scopus.com/inward/record.url?scp=85069726590&partnerID=8YFLogxK
U2 - 10.1016/j.jmbbm.2019.05.040
DO - 10.1016/j.jmbbm.2019.05.040
M3 - Article
C2 - 31349141
AN - SCOPUS:85069726590
VL - 98
SP - 383
EP - 394
JO - Journal of the Mechanical Behavior of Biomedical Materials
JF - Journal of the Mechanical Behavior of Biomedical Materials
SN - 1751-6161
ER -