Odontoblast-like cell differentiation and dentin formation induced with TGF-β1

To investigate the inductive potential of scaffold material combing with transforming growth factor-β1 (TGF-β1), and to induce odontoblast differentiation and dentin formation from dental pulp cells both in vitro and in vivo.

Primarily cultured dental pulp cells were used for MTT, ALP activity assay and Alizarin red staining in the presence of TGF-β1. Pelleted cells were put on the filters combining with or not with TGF-β1 and cultured in vitro or in vivo. The in vitro and in vivo cell response and tissue formation were analysed with Haematoxylin-Eosin (HE), transmission electron microscopy (TEM) and immunohistochemical staining.

TGF-β1 increased the mineralization and ALP activity of dental pulp cells as revealed by Alizarin red staining and ALP activity assay. After in vitro culture for 7 days, cells polarized in the TGF-β1 group and expressed dentin sialoprotein (DSP), osteopontin (OPN) and type I collagen (Col I). After in vivo transplantation for 7 days, columnar odontoblast formed on the surface of filter in experimental group, and tubular dentin expressing DSP formed after 3 months transplantation.

It was concluded that TGF-β1 combining with transfilter could induce odontoblast differentiation and dentin formation. Our results implied that suitable substrate for the progenitors of odontoblast to anchor on and inductive signals to initiate the differentiation of odontoblast should be taken into consideration when designing scaffold material for inducing dentin tissue engineering.