in impacted cartilage
explants varies with the presence of underlying bone.
Krueger, JA, Thisse, P, Ewers, BJ, Dvoracek-Dricksna,
D, Orth, MW, Haut, RC.
ABSTRACT:
Excessive mechanical loading
can lead to matrix damage and chondrocyte death in articular cartilage.
Previous studies on chondral and osteochondral explants have not clearly
distinguished to what extent the degree and the distribution of cell death are
dependent on the presence of an underlying layer of bone. The current study
hypothesized that the presence of underlying bone would decrease the amount of
matrix damage and cell death. Chondral and osteochondral explants were loaded
to 30 MPa at a high rate of loading (~600 MPa/s) or at a low rate of loading
(30 MPa/s). After 24 hours in culture, matrix damage was assessed by the total
length and average depth of surface fissures. The explants were also sectioned
and stained for cell viability in the various layers of the cartilage. More
matrix damage was documented in chondral than osteochondral explants for each
rate of loading experiment. The total amount of cell death was also less in
osteochondral explants than chondral explants. The presence of underlying bone
significantly reduced the extent of cell death in all zones in low rate of
loading tests. The percentage of cell death was also reduced in the
intermediate zone and deep zones of the explant by the presence of the
underlying bone for a high rate of loading. This study indicated that the
presence of underlying bone significantly limited the degree of matrix damage
and cell death, and also affected the distribution of dead cells through the
explant thickness. These data may have relevance to the applicability of
experimental data from chondral explants to the in situ condition.
Orthopaedic Biomechanics Laboratories,
College of
Osteopathic Medicine,
Michigan
State University,
East Lansing,
Michigan 48824
Please address correspondence to:
Roger C. Haut, Ph.D.,
Orthopaedic
Biomechanics Laboratory,
College of
Osteopathic Medicine,
A414 East Fee
Hall,
Michigan
State University,
East Lansing,
MI 48824,
Tel:
(517)355-0320,
Fax: (517)353-0789,
E-mail: haut@msu.edu