Abstract
BackgroundCartilage degeneration via osteoarthritis affects millions of elderly people worldwide, yet the specific contributions of matrix biopolymers toward cartilage viscoelastic properties remain unknown despite 30 years of research. Polymer dynamics theory may enable such an understanding, and predicts that cartilage stress-relaxation will proceed faster when the average polymer length is shortened.MethodsThis study tested whether the predictions of polymer dynamics were consistent with changes in cartilage mechanics caused by enzymatic digestion of specific cartilage extracellular matrix molecules. Bovine calf cartilage explants were cultured overnight before being immersed in type IV collagenase, bacterial hyaluronidase, or control solutions. Stress-relaxation and cyclical loading tests were performed after 0, 1, and 2 days of incubation.ResultsStress-relaxation proceeded faster following enzymatic digestion by collagenase and bacterial hyaluronidase after 1 day of incubation (both p ≤ 0.01). The storage and loss moduli at frequencies of 1 Hz and above were smaller after 1 day of digestion by collagenase and bacterial hyaluronidase (all p ≤ 0.02).ConclusionThese results demonstrate that enzymatic digestion alters cartilage viscoelastic properties in a manner consistent with polymer dynamics mechanisms. Future studies may expand the use of polymer dynamics as a microstructural model for understanding the contributions of specific matrix molecules toward tissue-level viscoelastic properties.
Highlights
Cartilage degeneration via osteoarthritis affects millions of elderly people worldwide, yet the specific contributions of matrix biopolymers toward cartilage viscoelastic properties remain unknown despite 30 years of research
This study examines the molecular origins of cartilage viscoelastic deformations in the context of polymer dynamics
The proteoglycan aggregate consists of the glycosaminoglycans keratin and chondroitin sulfate which are covalently bound to the protein aggrecan which noncovalently binds with hyaluronan [8]
Summary
Cartilage degeneration via osteoarthritis affects millions of elderly people worldwide, yet the specific contributions of matrix biopolymers toward cartilage viscoelastic properties remain unknown despite 30 years of research. Osteoarthritis is the most prevalent debilitating joint disease involving deterioration of the articular cartilage [1], yet the contributions of specific cartilage extracellular matrix molecules toward tissue-level viscoelastic mechanical properties are not sufficiently understood to enable specific osteoarthritis therapeutic strategies. Since cartilage deforms during in vivo loading, understanding the specific molecular origins of cartilage resistance to deformation is necessary to understand cartilage mechanical function. This study examines the molecular origins of cartilage viscoelastic deformations in the context of polymer dynamics. The cartilage extracellular matrix is primarily composed of two polymers [6]: collagen and the proteoglycan aggregate. The proteoglycan aggregate consists of the glycosaminoglycans keratin and chondroitin sulfate which are covalently bound to the protein aggrecan which noncovalently binds with hyaluronan [8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
