Time, stress, and location dependent chondrocyte death and collagen damage in cyclically loaded articular cartilage

Chih Tung Chen, Madhu Bhargava, Peggy M. Lin, Peter A. Torzilli

Research output: Contribution to journalArticle

118 Scopus citations

Abstract

We investigated the effect of light (0.1 MPa), moderate (1 MPa) or heavy (5 MPa) cyclical stresses applied continuously or intermittently for 0 to 72 h on cell death and collagen damage in adult bovine cartilage explants. No increase in cell death was observed in the cartilage loaded with a continuous cyclic stress at 0.1 MPa for up to 72 h. Cell death occurred in the uppermost superficial tangential zone (STZ) of explants after loading for 1 h at 1 MPa, and reached a maximum depth of 61 ± 23 μm by 6 h (at the rate of 9 ± 6 μm/h). At 5 MPa, cell death occurred in the STZ after as little as 1 min (30 cycles) of loading, and reached a maximum depth of 70 ± 2 μm by 60 min (47 ± 8 μm/h). When an intermittent (with 2 s on, 2 s off) stress of 5 MPa was applied, cell death appeared in the STZ after 2 min (30 cycles) and increased to a depth of 63 ± 2 μm at 60 min (45 ± 11 μm/h). No significant differences were observed between the continuous and intermittent loading conditions. Both collagenase-cleaved and denatured collagen fibers were found in the STZ of explants loaded at 1 and 5 MPa. We concluded that load-induced cell death depends on load duration and magnitude, and that the chondrocytes in the STZ are more vulnerable to load-induced injury than those in the middle and deep zones.

Original languageEnglish (US)
Pages (from-to)888-898
Number of pages11
JournalJournal of Orthopaedic Research
Volume21
Issue number5
DOIs
StatePublished - Jan 1 2003

Keywords

  • Articular cartilage
  • Cell death
  • Collagen damage
  • Repetitive loads
  • Superficial tangential zone

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

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