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Updated: Aug 26, 2026
Real-time Visualization and Analysis of Chondrocyte Injury Due to Mechanical Loading in Fully Intact Murine Cartilage Explants
Published on: January 7, 2019
Ultrastructural quantification of cell death after injurious compression of bovine calf articular cartilage
P Patwari1, V Gaschen, I E James
1Continuum Electromechanics Lab, Center for Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. pkp@mit.edu
Objective:
It has been suggested that chondrocyte death by apoptosis may play a role in the pathogenesis of cartilage destruction in osteoarthritis, but the results of in-vivo and in-vitro investigations have been conflicting. To investigate further the cell death in our in-vitro model for traumatic joint injury, we performed a quantitative analysis by electron microscopy (EM) of cell morphology after injurious compression. For comparison, the TUNEL assay was also performed.
Design:
Articular cartilage explant disks were harvested from newborn calf femoropatellar groove. The disks were subjected to injurious compression (50% strain at a strain rate of 100%/s), incubated for 3 days, and then fixed for quantitative morphological analysis.
Results:
By TUNEL, the cell apoptosis rate increased from 7 +/- 2% in unloaded controls to 33 +/- 6% after injury (P=0.01; N=8 animals). By EM, the apoptosis rate increased from 5 +/- 1% in unloaded controls to 62 +/- 10% in injured cartilage (P=0.02, N=5 animals). Analysis by EM also identified that of the dead cells in injured disks, 97% were apoptotic by morphology.
Conclusions:
These results confirm a significant increase in cell death after injurious compression and suggest that most cell death observed here was by an apoptotic process.
