2008 年 6 巻 2 号 p. 88-96
In vitro differentiation induction of normal human periodontal ligament fibroblasts, HpdLF, into an osteoblast lineage was attempted and the changes in gene expression were examined. The cells changed to an osteoblast-like cuboid morphology at 3 weeks after induction. Moreover, calcified nodules were detected and osteocalcin expression was confirmed at 3 weeks after induction, suggesting that the differentiation was progressing toward an osteoblast lineage. The expression of bone differentiation markers such as alkaline phosphatase, type 1 collagen, insulin-like growth factor (IGF) 1, IGF2, bone morphogenic protein 2 (BMP2) and osteocalcin at 3 weeks after induction were increased compared with pre-induction. The up-regulation of IGF1 or IGF2 may be due to activation of pathways for the induction of alkaline phosphatase and type 1 collagen, and the differentiation of HpdLF into an osteoblast lineage. The increased expression of BMP2 may be due to the production of osteocalcin and maturation of osteoblasts.