Abstract
The bone-cartilage unit (BCU) is a universal feature in diarthrodial joints, which is mechanically-graded and subjected to shear and compressive strains. Changes in the BCU have been linked to osteoarthritis (OA) progression. Here we report existence of a physiological internal strain gradient (pre-strain) across the BCU at the ultrastructural scale of the extracellular matrix (ECM) constituents, specifically the collagen fibril. We use X-ray scattering that probes changes in the axial periodicity of fibril-level D-stagger of tropocollagen molecules in the matrix fibrils, as a measure of microscopic pre-strain. We find that mineralized collagen nanofibrils in the calcified plate are in tensile pre-strain relative to the underlying trabecular bone. This behaviour contrasts with the previously accepted notion that fibrillar pre-strain (or D-stagger) in collagenous tissues always reduces with mineralization, via reduced hydration and associated swelling pressure. Within the calcified part of the BCU, a finer-scale gradient in pre-strain (0.6% increase over ~50μm) is observed. The increased fibrillar pre-strain is linked to prior research reporting large tissue-level residual strains under compression. The findings may have biomechanical adaptative significance: higher in-built molecular level resilience/damage resistance to physiological compression, and disruption of the molecular-level pre-strains during remodelling of the bone-cartilage interface may be potential factors in osteoarthritis-based degeneration.
Funder
Engineering and Physical Sciences Research Council
Biotechnology and Biological Sciences Research Council
Medical Research Council
Diamond Light Source
Publisher
Public Library of Science (PLoS)
Reference56 articles.
1. Changes in the osteochondral unit during osteoarthritis: Structure, function and cartilage bone crosstalk;SR Goldring;Nature Reviews Rheumatology,2016
2. Bone-cartilage interface crosstalk in osteoarthritis: Potential pathways and future therapeutic strategies;XL Yuan;Osteoarthritis and Cartilage,2014
3. Global, regional, and national incidence, prevalence, and years lived with disability for 354 Diseases and Injuries for 195 countries and territories, 1990–2017: A systematic analysis for the Global Burden of Disease Study 2017.;SL James;Lancet,2018
4. Global, regional prevalence, incidence and risk factors of knee osteoarthritis in population-based studies;A Cui;EClinicalMedicine,2020
5. Biomarkers of (osteo)arthritis;A Mobasheri;Biomarkers,2015
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献