Linkage of chondrocyte apoptosis and cartilage degradation in human osteoarthritis

S Hashimoto, RL Ochs, S Komiya… - Arthritis & Rheumatism …, 1998 - Wiley Online Library
S Hashimoto, RL Ochs, S Komiya, M Lotz
Arthritis & Rheumatism: Official Journal of the American College …, 1998Wiley Online Library
Objective To examine the occurrence of apoptosis in human osteoarthritis (OA) cartilage,
and to determine its relationship to cartilage degradation. Methods Knee cartilage was
obtained from subjects at autopsy, from a tissue bank, and from OA patients undergoing total
joint replacement surgery. Chondrocytes were isolated and the number of apoptotic cells
was analyzed by flow cytometry. Apoptotic cells in cartilage sections were identified by the
detection of DNA strand breaks. Electron microscopy was applied to demonstrate …
Objective
To examine the occurrence of apoptosis in human osteoarthritis (OA) cartilage, and to determine its relationship to cartilage degradation.
Methods
Knee cartilage was obtained from subjects at autopsy, from a tissue bank, and from OA patients undergoing total joint replacement surgery. Chondrocytes were isolated and the number of apoptotic cells was analyzed by flow cytometry. Apoptotic cells in cartilage sections were identified by the detection of DNA strand breaks. Electron microscopy was applied to demonstrate morphologic changes, and Safranin O staining was performed to analyze the relationship between apoptosis and proteoglycan depletion.
Results
Flow cytometry on cell suspensions prepared from collagenase digests of cartilage showed that ∼22.3% of OA chondrocytes and 4.8% of normal chondrocytes were undergoing apoptosis. Staining of cartilage sections demonstrated the presence of apoptotic cells in the superficial and middle zones. Cartilage areas that contained apoptotic cells showed proteoglycan depletion, and the number of apoptotic cells was significantly correlated with the OA grade.
Conclusion
These observations demonstrate increased chondrocyte apoptosis in OA cartilage. Chondrocyte apoptosis and proteoglycan depletion are anatomically linked and may be mechanistically related.
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