Behavior of human dental pulp cells exposed to transforming growth factor-beta1 and acidic fibroblast growth factor in culture

The development of methods for regenerative endodontic procedures requires an understanding of the factors regulating the development of odontoblasts from adult cell populations such as pulpal cell lines. In this study, we exposed cultures of human pulp cells (7th passage) to growth factors including transforming growth factor-beta1 (TGF-beta1, at 1 or 5 ng/mL), acidic fibroblast growth factor (aFGF, 5 ng/mL), or a combination of the 2 growth factors and evaluated cellular morphology and markers of cell phenotype including alkaline phosphatase activity, osteocalcin, bone sialoprotein (BSP), and dentin sialophosprotein (DSPP). The mean number of nucleoli in the 1 ng/mL TGF-beta1 group was significantly higher than with 5 ng/mL aFGF. Alkaline phosphatase activity was significantly greater with 1 ng/mL TGF-beta1 versus 5 ng/mL TGF-beta1 + 5 ng/mL aFGF (P < .05). Osteocalcin mRNA was expressed in all samples. The cells exposed to 1 ng/mL TGF-beta1 were stimulated; however, exposure to growth factors for 8 days was not sufficient for expression of BSP and DSPP mRNA. Cells treated with 1 ng/mL TGF-beta1 exhibited higher activity, whereas 5 ng/mL aFGF-treated cells were inhibited. Although osteocalcin was observed in all cultures, suggestive of the potential for odontoblast formation, under the present conditions, the exposure to TGF-beta1 and aFGF was not sufficient to induce expression of the dentin matrix components BSP and DSPP.