Matrix and cell injury due to sub‐impact loading of adult bovine articular cartilage explants: effects of strain rate and peak stress

Mechanical overloading of cartilage has been implicated in the initiation and progression of osteoarthrosis. Our objectives were to identify threshold levels of strain rate and peak stress at which sub‐impact loads could induce cartilage matrix damage and chondrocyte injury in bovine osteochondral explants and to explore relationships between matrix damage, spatial patterns of cell injury, and applied loads. Single sub‐impact loads characterized by a constant strain rate between 3 × 10−5 and 0.7 s−1 to a peak stress between 3.5 and 14 MPa were applied, after which explants were maintained in culture for four days. At the higher strain rates, matrix mechanical failure (tissue cracks) and cell deactivation were most severe near the cartilage superficial zone and were associated with sustained increased release of proteoglycan from explants. In contrast, low strain rate loading was associated with cell deactivation in the absence of visible matrix damage. Furthermore, cell activity and proteoglycan synthesis were suppressed throughout the cartilage depth, but in a radially dependent manner with the most severe effects at the center of cylindrical explants. Results highlight spatial patterns of matrix damage and cell injury which depend upon the nature of injurious loading applied. These patterns of injury may also differ in terms of their long‐term implications for progression of degradative disease and possibilities for cartilage repair. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

[1]  Slemenda Cw The epidemiology of osteoarthritis of the knee. , 1992 .

[2]  F. Blanco,et al.  Osteoarthritis chondrocytes die by apoptosis. A possible pathway for osteoarthritis pathology. , 1998, Arthritis and rheumatism.

[3]  A. Maroudas,et al.  Balance between swelling pressure and collagen tension in normal and degenerate cartilage , 1976, Nature.

[4]  T. Kubo,et al.  Differences in the repair process of longitudinal and transverse injuries of cartilage in the rat knee. , 1998, Osteoarthritis and cartilage.

[5]  E B Hunziker,et al.  Mechanical compression alters proteoglycan deposition and matrix deformation around individual cells in cartilage explants. , 1998, Journal of cell science.

[6]  T. Oegema,et al.  Immunolocalization of selected cytokines and proteases in canine articular cartilage after transarticular loading , 1993, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[7]  P. Atkinson,et al.  Subfracture insult to the human cadaver patellofemoral joint produces occult injury , 1995, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[8]  E B Hunziker,et al.  Physical and Biological Regulation of Proteoglycan Turnover around Chondrocytes in Cartilage Explants: Implications for Tissue Degradation and Repair , 1999, Annals of the New York Academy of Sciences.

[9]  A. Grodzinsky,et al.  Mechanical regulation of cartilage biosynthetic behavior: physical stimuli. , 1994, Archives of biochemistry and biophysics.

[10]  R. Haut,et al.  Subfracture insult to a knee joint causes alterations in the bone and in the functional stiffness of overlying cartilage , 1997, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[11]  P. Torzilli,et al.  Effect of impact load on articular cartilage: development of an intra-articular fracture model. , 1997, Journal of orthopaedic trauma.

[12]  A. Grodzinsky,et al.  Effects of compression on the loss of newly synthesized proteoglycans and proteins from cartilage explants. , 1991, Archives of biochemistry and biophysics.

[13]  A. W. Rogers Techniques of autoradiography , 1967 .

[14]  W. A. Hodge,et al.  Contact pressures in the human hip joint measured in vivo. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[15]  A. Grodzinsky,et al.  Effects of injurious compression on matrix turnover around individual cells in calf articular cartilage explants , 1998, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[16]  Z. Darżynkiewicz,et al.  Assays of cell viability: discrimination of cells dying by apoptosis. , 1994, Methods in cell biology.

[17]  V. Hascall,et al.  Turnover of proteoglycans in cultures of bovine articular cartilage. , 1984, Archives of biochemistry and biophysics.

[18]  D. Buttle,et al.  Improved quantitation and discrimination of sulphated glycosaminoglycans by use of dimethylmethylene blue. , 1986, Biochimica et biophysica acta.

[19]  J B Finlay,et al.  Survival of articular cartilage after controlled impact. , 1977, The Journal of bone and joint surgery. American volume.

[20]  E. Hunziker,et al.  A method of quantitative autoradiography for the spatial localization of proteoglycan synthesis rates in cartilage. , 1996, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[21]  J. E. Jeffrey,et al.  Matrix damage and chondrocyte viability following a single impact load on articular cartilage. , 1995, Archives of biochemistry and biophysics.

[22]  J. Bertram,et al.  Swelling and fibronectin accumulation in articular cartilage explants after cyclical impact , 1996, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[23]  J. Lewis,et al.  Scanning electron-microscopic and magnetic resonance-imaging studies of injuries to the patellofemoral joint after acute transarticular loading. , 1993, The Journal of bone and joint surgery. American volume.

[24]  J. Lane,et al.  Long-term effects of chondrocyte death on rabbit articular cartilage in vivo. , 1976, The Journal of bone and joint surgery. American volume.

[25]  E. Radin,et al.  Effects of mechanical loading on the tissues of the rabbit knee , 1984, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[26]  H J Mankin,et al.  Articular cartilage: degeneration and osteoarthritis, repair, regeneration, and transplantation. , 1998, Instructional course lectures.

[27]  R. Haut,et al.  Impact-induced fissuring of articular cartilage: an investigation of failure criteria. , 1998, Journal of biomechanical engineering.