Tenascin-C promotes differentiation of rat dental pulp cells in vitro

To investigate the effects of tenascin-C (TN-C) on cultured rat dental pulp cells in relation to the expression of Notch signalling.

Subcultured dental pulp cells derived from rat incisors were seeded both in wells and on plastic coverslips coated with various concentrations of recombinant human TN-C. Expression of bone-related mRNA was then analysed by RT-PCR and observed by immunohistochemical staining. Encoding of Notch1 and Notch2 (markers of initial differentiation of odontoblast-like cells), alkaline phosphatase (ALP), osteopontin (OPN) and osteocalcin (OCN) (markers of mineralization) was investigated. Non-TN-C-coated wells were used as controls. Primary antibodies to Notch1, ALP and OCN were used for immunofluorescence staining, and ALP activity was evaluated. Data were compared using Student's t-test.

Cell proliferation rate in the experimental groups was significantly higher (P < 0.05) than that in the control group at 72 h. Expression of Notch1, Notch2, ALP, OPN and OCN mRNAs was significantly higher (P < 0.05) in the experimental group than that in the control group. Strongly positive staining for Notch1, ALP and OCN was observed in the experimental group. ALP activity was significantly higher (P < 0.01) in the experimental group than in the control group at 24 h.

TN-C promoted differentiation of rat dental pulp cells by the activation of Notch.