Biocompatibility of magnesium implants in primary human reaming debris-derived cells stem cells in vitro

BACKGROUND: Use of magnesium for resorbable metal implants is a new concept in orthopaedic and dental medicine. The majority of studies on magnesium’s biocompatibility in vitro have assessed the short-term effect of magnesium extract on cells. The aim of this study was to evaluate the influence of direct exposure to magnesium alloys on the bioactivity of primary human reaming debris-derived (HRD) cells. MATERIALS AND METHODS: Pure Mg, Mg2Ag, WE43 and Mg10Gd were tested for biocompatibility. The study consisted of assessment of cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test, evaluation of alkaline phosphatase (ALP) content, and study of cell morphology under light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), along with determination of calcification and pH changes induced by magnesium. RESULTS: The number of viable cells in the presence of Mg2Ag was high over the entire observation period. Inhibition of ALP content in osteogenic differentiating HRD was caused by pure Mg at day 14 and 28. All other magnesium alloys did not affect the ALP content. Exposure of HRD to magnesium increased the amount of lysosomes and endocytotic vesicles. Cellular attachment was generally the best for those crystals that formed on the surface of all materials. A decrease was observed in Ca(2+) in the medium from day 1 to day 14. CONCLUSIONS: In terms of cell morphology, cell viability and differentiation, cell density and the effect on the surrounding pH, Mg2Ag showed the most promising results. All magnesium materials induced calcification, which is beneficial for orthopaedic and dental applications.