Phagocytosis of Hydroxyapatite or Calcium Pyrophosphate Dihydrate Crystals by Rabbit Articular Chondrocytes Stimulates Release of Collagenase, Neutral Protease, and Prostaglandins E2 and F

Herman S. Cheung, Paul B. Halverson, Daniel J. McCarty

Research output: Contribution to journalArticle

45 Scopus citations


Synthetic hydroxyapatite (HA) and calcium pyrophosphate dihydrate (CPPD) microcrystals are phagocytosed by rabbit articular-cartilage chondrocytes in primary culture. The ingestion of crystals greatly stimulated the release of collagenase, neutral protease, and prostaglandins E2 and F(2α) into the ambient medium. Lactate dehydrogenase was not released by either crystal despite electron microscopic evidence of cell damage by HA crystals (partial loss of phagolysosomal membrane and increased myelin figures). HA, but not CPPD crystals, stimulated release of β-glucuronidase. HA crystal concentrations from 50 to 200 μg ml-1 induced a dose-dependent release of collagenase and of extracellular protein. Both phagocytosis and collagenase release were greatly attenuated when HA crystals were added to the chondrocyte monolayers in the absence of serum. As HA and CPPD crystals have been identified in human articular cartilage in association with degenerative changes, it is possible that the cell-crystal interaction described here may be pathogenetically important.

Original languageEnglish (US)
Pages (from-to)181-189
Number of pages9
JournalProceedings of the Society for Experimental Biology and Medicine
Issue number2
StatePublished - Jun 1983
Externally publishedYes


ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this