Effects of different concentrations of degradation products of magnesium and magnesium alloys on osteogenic precursor cells

Magnesium-based alloys have a great potential to become orthopedic
degradable materials for internal fixation implants, and magnesium-based
implants have been shown to influence the surrounding bone structure. To
understand the effects of magnesium-based implants on bone healing and
remodeling, we investigated the effects of the extracts of pure magnesium
and three magnesium alloys on the proliferation and differentiation of
osteogenic precursor cells in vitro. MC3T3-E1 cells were selected as the
study objects. Cell culture medium was used to extract the aforementioned
metal materials, and the degradation products and extracts were subjected
to a compositional analysis. Subsequently, the extracts were diluted to
different concentrations for cell proliferation/differentiation cultures.
The MC3T3-E1 proliferation and differentiation were evaluated based on the
cell viability, alkaline phosphatase activity, total protein content, and
cellular ability to form calcified nodules in the extracellular matrix.The
magnesium ions enhanced and opposed cell proliferation and differentiation
in a concentration-dependent manner. Higher concentrations of metal
extracts that degraded faster (indicating higher levels of Mg ions) had an
adverse effect on cell proliferation, and extracts with a lower
concentration or slower degradation promoted cell proliferation. When
slightly elevated, the Mg ions in the extracts suppressed the osteogenic
differentiation and extracellular matrix mineralization of the cells,
while they promoted these processes when present beyond a certain
concentration. In cases of similar Mg ion contents, the extracts that
contained Zn ions were better in promoting cell proliferation and
extracellular matrix mineralization.