Effects of TGFβ1 on dental pulp cells in cultured human tooth slices

Transforming Growth Factor-beta1 (TGF beta 1) is a potent modulator of tissue repair in various tissues. To analyze its role during human dental repair, we used thick-sliced teeth cultured as described previously (Magloire et al., 1996). The supply of TGF beta 1 to the pulp tissue was accomplished by means of a small tube glued onto the dentin. We show that this device allowed the growth factor to diffuse locally through dentinal tubules and to bind to the cells present in the coronal pulp opposite the TGF beta 1-delivery tube. The tube was filled with 20 ng/mL TGF beta 1, and slices were cultured for 4 days. Results show a preferential accumulation of cells in the odontoblastic and subodontoblastic layers in the vicinity of the tube. Cell proliferation increased in the subodontoblastic layer and in the underlying pulp, and BrdU-positive cells were abundant around the blood vessels. TGF beta 1 induced type I collagen production by the odontoblastic/subodontoblastic/pulp cells in the stimulated zone, as demonstrated by in situ hybridization. These results suggest that TGF beta 1 could be directly involved in the regulation of cell proliferation, migration, and extracellular matrix production in the human dental pulp and eventually in the repair process occurring after tooth injury.