Lj. Bonassar et al., CHANGES IN CARTILAGE COMPOSITION AND PHYSICAL-PROPERTIES DUE TO STROMELYSIN DEGRADATION, Arthritis and rheumatism, 38(2), 1995, pp. 173-183
Objective. To determine the effects of stromelysin treatment on bioche
mical, histologic, and swelling characteristics of intact cartilage ex
plants and to correlate these effects with changes in the functional p
hysical properties of the tissue. Methods. Bovine articular cartilage
explants were cultured for up to 3 days in the presence or absence of
recombinant human stromelysin (SLN). Damage to matrix proteoglycans an
d collagens was assessed and characterized by N-terminal sequencing an
d Western blot analysis, respectively. Explants were mechanically test
ed to assess the ability of the tissue to withstand cyclic and static
compressive loads. Results. Treatment with SLN resulted in a time- and
dose-dependent loss of proteoglycans from cartilage explants, with si
gnificant loss seen after 3 days of exposure to 20 nM SLN. Histology i
ndicated that initial loss of proteoglycans occurred in regions near t
he tissue surface and proceeded inward with increasing time of SLN exp
osure. SLN treatment resulted in degradation of matrix collagen types
IX and II, and a concomitant increase in tissue swelling. This matrix
degradation resulted in severe alterations in functional physical prop
erties of the tissue, including compressive stiffness. The initial, fo
cal loss of proteoglycans that resulted from SLN treatment was most ac
curately detected with high-frequency streaming potential measurements
. Conclusion. Exposure of intact cartilage to SLN caused specific, mol
ecular-level degradation of matrix molecules, which resulted in change
s in the swelling behavior and marked deterioration of functional phys
ical properties of the tissue.