Gene expression of osteogenic cells exposed to calcium aluminate cement

Objective: The aim of this study was to evaluate the effect of a novel calcium aluminate cement (CAC+) on gene expression of key osteoblastic markers in primary osteogenic cell cultures.

Method: Osteogenic cells were enzimatically isolated from newborn rat calvarial bone, plated on Thermanox coverslips at 20,000 cells/well, and cultured for up to 10 days. CAC+ and mineral trioxide aggregate (MTA) specimens (4 mm in diameter and 2 mm height) were prepared according to manufacturer’s guidelines under sterile conditions and allowed to solidify in silicon templates for 4 hours. CAC+ and MTA specimens were placed on polycarbonate inserts (pore size, 3 µm) and cell exposure was performed during either the proliferative (days 2-5) or the differentiation phase (days 7-10). Gene expression of runt-related transcription factor 2 (RUNX-2), alkaline phosphatase (ALP), osteocalcin (OC), osteopontin (OPN), bone sialoprotein (BSP), and osterix (OST) was assessed by means of Real-Time PCR at days 7 and 10. Comparisons were carried out using the non-parametric Kruskal-Wallis test (p < 0.05).

Result: At day 7, cultures exposed to CAC+ during the proliferative phase exhibited a higher gene expression of RUNX-2, ALP, and BSP, while OPN expression was greater in cultures exposed to MTA. At day 10, a higher expression of RUNX-2, ALP, OC, BSP, and OST was noticed for cells exposed to CAC+ during the proliferative phase. Cultures exposed to CAC+ at differentiation phase showed a greater expression of RUNX-2 and BSP, whereas those exposed to MTA exhibited a higher expression of OPN.

Conclusion: These results indicate that CAC+ supports the up-regulation of key markers of osteoblastic differentiation in osteogenic cell cultures irrespective of the timing of exposure.