Abstract:
TGF-[beta]1 is one of the growth factor that plays an important role in metabolism of bone and teeth The purpose of this study is to investigate the response of cultured human pulpal fibroblasts to TGF-[beta]1, especially the change in alkaline phosphatase (ALP) activity and the expression of osteocalcin. In addition we would like to compare these responses with the expression of BMP and BMPR. Pulpal fibroblasts were cultured in the presence of 0, 0.1, 1 and 10 ng/ml of TGF-[beta]1 for 3 and 5 days. The results indicated that the level of ALP activity increased in the group treated with 0.1 and 1 ng/ml of TGF-[beta]1 on day 5 as compared to the control. However there was no difference in the expression of osteocalcin on both day 3 and 5. The expression of BMP-2, BMP-4, BMPR-IA and BMPR-II also increased in the groups treated with 0.1 and 1 ng/ml of TGF-[beta]1 for 5 days similar to the ALP activity. Next, cells were treated with 0.1 and 1 ng/ml of TGF-[beta]1 in 2 different experimental designs. The first group was grown in the presence of TGF-[beta]1 for 7 days. In the second group. TGF-[beta]1 was withdrawn from the medium after 5 days treatment and cultured for another 2 days. Only ALP activity was increased up to 8 folds in the preence of TGF-[beta]1 in the first group. Surprisingly, the expression of osteocalcin increased 2 fold in the second group while ALP activity was only 2-3 fold higher than the control. Increased level of BMP-2, BMP-4, BMPR-IA and BMPR-II was also detected only in the second group. Upregulation of ALP and osteocalcin has been shown to indicate the process of cell differentiation, thus, we would like to conclude that TGF-[beta]1 can influence the differentiation of human pulpal fibroblasts in a dose and spatial dependent manner. The duration of TGF-[beta]1 presentation might also be one of the factors that involve in the differentiation process. Furthermore, since the upregulation of BMP and BMPR in this study also corresponds with the change in ALP activity and osteocalcin expression, we would like to propose that TGF-[beta]1 induce the pulpal cell differentiation through the BMP pathway.