Abstract:
Dental pulp fibroblasts have been shown to play role in dental pulp healing mechanism by differentiating into odontoblast-like cells. However, actual control of the mechanism is still unclear. In this study, we would like to examine the effect of 1,25(OH)[subscript 2]D[subscript 3] and TGF-{beta} on the expression of SPARC and OPN in primary culture of dental pulp fibroblasts. The results revealed that 0.1 to 10 nM of 1,25(OH)[subscript 2]D[subscript 3] could increase the expression of OPN, but not SPARC, within 3 days, and 0.1 to 10 ng/ml of TGF-{beta} could increase the expression of both OPN and SPARC. When cells were cultured in the presence of 1 nM of 1,25(OH)[subscript 2]D[subscript 3] combined with 1 ng/ml of TGF-{beta}, the level of mRNA of OPN was increased 13 fold, while those of the group treated with either 1,25(OH)[ subscript 2]D[subscript 3] or TGR-{beta} alone increased only 6 and 3 fold, respectively. However, the amount of OPN synthesis was not changed. The level of SPARC protein was also increased approximately 5 fold in the combined condition while the 1,25(OH)[ subscript 2]D[subscript 3] or TGF-{beta} treated groups showed only 1.8-and 3-fold increase, respectively. Nevertheless, the combined condition did not affect the amount of mRNA of SPARC. These results indicate that both 1,25(OH)[subscript 2]D[subscript 3] and TGF-{beta} can determine the pattern of protein synthesis in dental pulp fibroblasts which reflect the stage of differentiation in this cell type. Furthermore, the results also suggest the possibility of cross talk mechanism between these two factors that might involve in the regulation of dental pulp cell differentiation.