Journal
JOURNAL OF ORTHOPAEDIC RESEARCH
Volume 35, Issue 2, Pages 304-310Publisher
WILEY-BLACKWELL
DOI: 10.1002/jor.23260
Keywords
osteoarthritis; articular cartilage; impact loading; cell death; membrane reservoir
Categories
Funding
- Alberta Innovates-Health Solutions (AI-HS)
- AI-HS Team Grant on Osteoarthritis [200700596]
- NSERC CREATE Training Program of Biomedical Engineers [371280-2009]
- Canadian Institutes of Health Research (CIHR) [MOP-111205, 140824]
- CIHR Canada Research Chair [950-200955]
- Killam Memorial Chair
- Alberta Innovates [201500764] Funding Source: researchfish
Ask authors/readers for more resources
Impact loading results in chondrocyte death. Previous studies implicated high tensile strain rates in chondrocyte membranes as the cause of impact-induced cell deaths. However, this hypothesis relies on the untested assumption that chondrocyte membranes unfold in vivo during physiological tissue compression, but do not unfold during impact loading. Although membrane unfolding has been observed in isolated chondrocytes during osmotically induced swelling and mechanical compression, it is not known if membrane unfolding also occurs in chondrocytes embedded in their natural extracellular matrix. This study was aimed at quantifying changes in membrane morphology of in situ superficial zone chondrocytes during slow physiological cartilage compression. Bovine cartilage-bone explants were loaded at 5m/s to nominal compressive strains ranging from 0% to 50%. After holding the final strains for 45min, the loaded cartilage was chemically pre-fixed for 12h. The cartilage layer was post-processed for visualization of cell ultrastructure using electron microscopy. The changes in membrane morphology in superficial zone cells were quantified from planar electron micrographs by measuring the roughness and the complexity of the cell surfaces. Qualitatively, the cell surface ruffles that existed before loading disappeared when cartilage was loaded. Quantitatively, the roughness and complexity of cell surfaces decreased with increasing load magnitudes, suggesting a load-dependent use of membrane reservoirs. Chondrocyte membranes unfold in a load-dependent manner when cartilage is compressed. Under physiologically meaningful loading conditions, the cells likely expand their surface through unfolding of the membrane ruffles, and therefore avoid direct stretch of the cell membrane. (c) 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:304-310, 2017.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available