title: Comparison of spontaneous and retinoic acid stimulated rabbit articular cartilage degradation in vitro.
abstract: The in vitro degradation of rabbit articular cartilage explants was evaluated with and without the addition of retinoic acid under various experimental conditions. Retinoic acid at nontoxic concentrations ranging from 1 X 10(-7) to 1 X 10(-5) M significantly increased cartilage degradation. The addition of phenanthroline or cycloheximide, but not pepstatin, significantly inhibited spontaneous and retinoic-acid-stimulated cartilage degradation at pH 7. When the pH was reduced to 5, only pepstatin inhibited spontaneous and retinoic-acid-stimulated cartilage degradation. No chondroitin sulphate release was observed when the temperature was reduced to 4 degrees C. The different inhibitory profiles observed at pH 7 and pH 5 suggest that cartilage degradation at pH 7 is associated with the presence and synthesis of a neutral metalloproteinase.
mesh_terms: D000818:Animals; D001329:Autolysis; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D010618:Phenanthrolines / Q000494:pharmacology; D011509:Proteoglycans / Q000378:metabolism; D011817:Rabbits; D013696:Temperature; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D010618:Phenanthrolines; D011509:Proteoglycans; D014212:Tretinoin; D003513:Cycloheximide