Solubilization of hydroxyapatite crystals by murine bone cells, macrophages and fibroblasts

Cheung Hing Kwong, William B. Burns, Herman S. Cheung

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Calcium phosphate ceramic is widely used as implant material. It is made up of hydroxyapatite, β-tricalcium phosphate or various combinations of both. In the present study, we use an in vitro model to examine the role of cell-mediated resorption of calcium phosphate ceramic implant material. We compare the abilities of two sequential enzymatic released populations of bone cells from murine calvaria (Population II and Population V), macrophages and dermal fibroblasts to solubilize 45Ca-labelled hydroxyapatite crystals. These crystals were incubated with each of the cell types for 24 h in the presence or absence of parathyroid hormone, prostaglandin E2, calcitonin, and 1, 25-dihydroxyvitamin D3. The amount of cell-mediated hydroxyapatite solubilization was determined by measuring the radioactivity in an aliquot of the supernatant after centrifugation. Using dermal fibroblasts as a baseline, relative abilities of macrophages. Population II and Population V to degrade crystals were 10.5, 5 and 2 times that of fibroblasts. Crystal-cell contact was required. While none of the bone resorption agents tested had any effect on this process, crystal dissolution by bone cells was inhibited by two lysosomotropic agents, NH4CI and chloroquine.

Original languageEnglish (US)
Pages (from-to)579-584
Number of pages6
Issue number9
StatePublished - Nov 1989
Externally publishedYes


  • bone
  • Hydroxyapatite
  • resorbable materials

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering


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