Abstract
Introduction: Cobalt-Chromium (Co-Cr) alloys are widely used in biomedicine owing to their resistance to corrosion, mechanical properties, and biocompatibility. Despite the increase in its use in orthopaedic surgery, a number of unique complications (elevated serum levels of Co and Cr ions, development of pseudotumour, neck narrowing, osteolysis and fracture) have been recently reported with Metal-on-Metal (MoM) bearings. The goal of the present study was to assess the effects of Co and Cr ions on human osteoblasts and human osteoclast biology.
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Materials and methods: Peripheral blood mononuclear cells (PBMCs) have been used as a source of osteoclast precursors whilst SaOS-2 cells have been used as osteoblasts. Both cell types have been cultured in the presence of Co2+ or Cr3+ ions.
Results: We have found that 100 μM Co2++ induced a significant increase in the number and the size of multinucleated tartrate resistant acid phosphatase positive osteoclasts as well as the number of nuclei per osteoclast. In contrast, 100 μM Cr3+ significantly decreased the number of newly-formed osteoclast but had no effect on the size or the number of nuclei per osteoclast. Interestingly, 100 μM of Co2+ was capable of strongly inhibiting bone resorption whereas 100 μM of Cr3+ had no significant effects on this parameter. The alkaline phosphatase activity was significantly increased by low concentrations of Co2+ and decreased by high concentrations of Cr3+ after 24 h and 48 h. Moreover, the degree of mineralization of a new bone matrix in vitro was significantly reduced when the SaOS-2 cells were exposed to high concentrations of Cr3+, but significantly increased when they were exposed to Co2+.
Discussion: These results suggest that long-term exposure to “chronic” levels of metal ions damages the functional behaviour of bone cells and subsequently may affect bone quality.
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Materials and methods: Peripheral blood mononuclear cells (PBMCs) have been used as a source of osteoclast precursors whilst SaOS-2 cells have been used as osteoblasts. Both cell types have been cultured in the presence of Co2+ or Cr3+ ions.
Results: We have found that 100 μM Co2++ induced a significant increase in the number and the size of multinucleated tartrate resistant acid phosphatase positive osteoclasts as well as the number of nuclei per osteoclast. In contrast, 100 μM Cr3+ significantly decreased the number of newly-formed osteoclast but had no effect on the size or the number of nuclei per osteoclast. Interestingly, 100 μM of Co2+ was capable of strongly inhibiting bone resorption whereas 100 μM of Cr3+ had no significant effects on this parameter. The alkaline phosphatase activity was significantly increased by low concentrations of Co2+ and decreased by high concentrations of Cr3+ after 24 h and 48 h. Moreover, the degree of mineralization of a new bone matrix in vitro was significantly reduced when the SaOS-2 cells were exposed to high concentrations of Cr3+, but significantly increased when they were exposed to Co2+.
Discussion: These results suggest that long-term exposure to “chronic” levels of metal ions damages the functional behaviour of bone cells and subsequently may affect bone quality.
| Original language | English |
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| Article number | 219 |
| Journal | Open Access Scientific Reports |
| Volume | 1 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 27 Jun 2012 |