Normal matrix mineralization induced by strontium ranelate in MC3T3-E1 osteogenic cells
Section snippets
Cell cultures and treatment
MC3T3-E1 are clonal osteogenic cells derived from newborn mouse calvaria25 that have a high mineralization potential.25, 26, 27, 28, 29 MC3T3-E1 cultured in the presence of ascorbic acid display a time-dependent and sequential expression of osteoblast characteristics analogous to the bone formation process in vivo.27 The cells actively replicate, then express alkaline phosphatase (ALP) activity and synthesize a collagenous extracellular matrix, which progressively undergoes mineralization.27 In
Sr increases ALP activity
The effects of SR (0.1, 0.5, and 1 mmol/L Sr2+) were first analyzed in MC3T3-E1 cells cultured from 4 to 14 days. In control cells, ALP activity increased transiently at 10 days. Treatment with 1,25(OH)2D (1 nmol/L) significantly increased ALP activity on day 4 (+45%), day 10 (+81%), and day 14 (+100 %) of culture compared with controls. Treatment with SR (1 mmol/L Sr2+) significantly increased ALP activity at day 4 (+45 %) and day 14 (+45 %) of culture compared with control conditions (Fig 1).
Discussion
We previously showed that SR has beneficial effects on bone mass in experimental models of osteopenia (reviewed in Marie31). Because Sr incorporates into bone (reviewed in Dahl et al20), it was important to determine whether SR might alter mineralization of the matrix in long-term culture. The present study shows that long-term in vitro treatment with SR does not hamper matrix mineralization induced by murine osteogenic cells.
MC3T3-E1 are osteogenic cells that are a widely used model to study
Acknowledgements
We thank thank Professor C. Rey for helpful discussions.
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