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Reproducible quantification of osteoclastic activity: Characterization of a biomimetic calcium phosphate assay
Author(s) -
Maria Salwa M.,
Prukner Christiane,
Sheikh Zeeshan,
Mueller Frank,
Barralet Jake. E.,
Komarova Svetlana V.
Publication year - 2014
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.33071
Subject(s) - osteoclast , bone resorption , rankl , chemistry , calcium , resorption , biochemistry , in vitro , medicine , receptor , activator (genetics) , organic chemistry
Abstract Osteoclasts are responsible for bone and joint destruction in rheumatoid arthritis, periodontitis, and osteoporosis. Animal tusk slice assays are standard for evaluating the effect of therapeutics on these cells. However, in addition to batch‐to‐batch variability inherent to animal tusks, their use is clearly not sustainable. Our objective was to develop and characterize a biomimetic calcium phosphate assay based on the use of phase pure hydroxyapatite coated as a thin film on the surface of culture plates, to facilitate the reproducible quantification of osteoclast resorptive activity. Osteoclasts were formed from RAW 264.7 mouse monocyte cell line using a pro‐resorptive cytokine RANKL (50 ng/mL). No change in substrate appearance was noted after culture with media without cells, or undifferentiated monocytes. Only in the presence of osteoclasts localized areas of calcium phosphate dissolution were observed. The total area resorbed positively correlated with the osteoclast numbers ( R 2 = 0.99). The resorbed area was significantly increased by the addition of RANKL, and decreased after application of known inhibitors of osteoclast resorptive activity, calcitonin (10 μ M ), or alendronate (100 μ M ). Thus, calcium phosphate coated substrates allow reliable monitoring of osteoclast resorptive activity and offer an alternative to animal tusk slice assays. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 903–912, 2014.