Synthetic octacalcium phosphate-enhanced reparative dentine formation via induction of odontoblast differentiation.
Synthetic octacalcium phosphate (OCP) has been suggested to be a useful biomaterial for the regeneration of hard tissues, including bone. However, it remains unknown whether OCP induces dentine formation by dental pulp. We investigated biomineralization of dental pulp exposed to synthetic OCP in vitro and in vivo. When dental pulp was exposed directly to OCP, rapid formation of reparative dentine (RD) was induced and expression of dentine sialoprotein synthesis was observed in dental pulp adjacent to newly synthesized RD. OCP inhibited the proliferation of rat pulp cells and also promoted their odontoblastic differentiation in vitro, as alkaline phosphatase activity, mineralization of pulp cells and the expression level of dentine sialophosphoprotein were enhanced. Direct contact between OCP and pulp cells is required for OCP to exhibit its effects in vitro. The expression level of Runx2, a transcription factor whose downregulation is closely related to odontoblast differentiation, was downregulated in pulp cells cultured with OCP. Structural changes of OCP during culture were determined by Fourier transform infrared spectroscopy. OCP tended to be converted to carbonate hydroxyapatite after incubation with or without pulp cells, which may be analogous to biological apatite crystals. Taken together, our data suggest that synthetic OCP supports RD formation by dental pulp and downregulation of Runx2 may be involved in that stimulatory activity. Furthermore, OCP-apatite conversion is involved in this stimulatory capacity of OCP.
Department of Biochemistry, Showa University School of Dentistry, Tokyo, Japan.
Xiaogu
X
Wang
Department of Biochemistry, Showa University School of Dentistry, Tokyo, Japan.
Tetsuo
T
Suzawa
Department of Biochemistry, Showa University School of Dentistry, Tokyo, Japan.
Tomohiko
T
Miyauchi
Department of Biochemistry, Showa University School of Dentistry, Tokyo, Japan.
Baohong
B
Zhao
Department of Biochemistry, Showa University School of Dentistry, Tokyo, Japan.
Rika
R
Yasuhara
Division of Craniofacial Function Engineering, Tohoku University Graduate School of Dentistry, Sendai, Japan.
Takahisa
T
Anada
Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, Tokyo, Japan.
Masanori
M
Nakamura
Division of Craniofacial Function Engineering, Tohoku University Graduate School of Dentistry, Sendai, Japan.
Osamu
O
Suzuki
Department of Biochemistry, Showa University School of Dentistry, Tokyo, Japan.
Ryutaro
R
Kamijo
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D002454:Cell Differentiation; D049109:Cell Proliferation; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism*; D003782:Dental Pulp / Q000378:metabolism*; D003804:Dentin / Q000737:chemistry*; D003809:Dentin, Secondary / Q000737:chemistry; D015536:Down-Regulation; D017886:Durapatite / Q000737:chemistry; D016326:Extracellular Matrix Proteins / Q000737:chemistry; D007150:Immunohistochemistry; D008297:Male; D008963:Molar / Q000378:metabolism; D009804:Odontoblasts / Q000166:cytology / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D000099311:Dentin Sialophosphoprotein
D000469:Alkaline Phosphatase; D001672:Biocompatible Materials; D002130:Calcium Phosphates; D002254:Carbonates; D050659:Core Binding Factor Alpha 1 Subunit; D017886:Durapatite; D016326:Extracellular Matrix Proteins; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C493717:Runx2 protein, rat; C022045:octacalcium phosphate
Runx2; biomineralization; dental pulp; dentine sialophosphoprotein; octacalcium phosphate (OCP); odontoblasts; reparative dentine