Objective: To investigate the effect of cytokines on in vitro bone resorption by cells isolated from giant cell tumor of bone.
Methods: Mononuclear stromal cells and multinucleated giant cells (MGC) were isolated from 11 cases of giant cell tumor of bone (GCT) and their bone resorption capability in an in vitro cell-bone resorption model were tested. Expressions of some cytokines were detected by immunohistochemistry, Western blotting analysis and Enzyme-linked immunoabsorbent assay (ELISA) in the GCT.
Results: The results showed that MGCs of GCT had capability to resorb bone matrix directly. Fibroblast-like stromal cells (FC) could not only resorb bone matrix directly, but also secret unknown factors to facilitate bone resorption of MGC. Exogenous TNF-alpha could significantly increase the bone resorption by both kinds of stromal cells, while exogenous IL-1 did not. Expression rate of M-CSF and level of TNF-alpha in GCT were higher than in osteosarcoma and normal serum.
Conclusions: The characteristic bone resorption behavior of GCT might be caused by its three major cell components. The M-CSF and TNF-alpha could promote their bone resorption capability.