Effects of degradable Mg-Ca alloys on dendritic cell function

Degradable magnesium alloys are new materials for implants used in orthopedic and trauma surgery. The aim of this study was to investigate the influence of degradable magnesium alloys on the function of dendritic cells (DC) as these cells represent the major antigen presenting cells of the body. MgP (pure magnesium), MgCa 0.6 (0.6% calcium), MgCa 0.8 (0.8% calcium), MgCa 1.0 (1% calcium), and MgCa 1.2 (1.2% calcium) alloys were degraded in cell culture medium. In parallel, murine bone marrow-derived DC were incubated with increasing concentrations (0.1-10 mmol/L) of magnesium chloride and calcium chloride, respectively. Incubation of DC with degradation media over 6 days had no influence on cell viability and only marginal influence on DC migration. Also, the production of TNFα and expression of CD86 was not enhanced by incubation with degraded magnesium alloys. The mixed leukocyte reaction revealed that there was also no increase of the T-cell proliferation in comparison to untreated controls. However, there was a trend toward macrophage development at the expense of DC expansion and an enhanced DC migration was induced by incubation with higher magnesium concentrations. Particularly the latter should be verified in in vivo experiments.