Different Roles of Dexamethasone on Transforming Growth Factor-β1–induced Fibronectin and Nerve Growth Factor Expression in Dental Pulp Cells

During pulp injury, it has been hypothesized that transforming growth factor-β1 (TGF-β1) is released from dentin into pulp tissue and promotes pulp tissue healing. Dexamethasone is a glucocorticoid that has been used to treat pulp injury and shown to induce differentiation of hard tissue forming cells. However, the interaction between dexamethasone and TGF-β1 is still unknown. This study aimed to examine the effects of dexamethasone on human pulp cells in the presence of TGF-β1. TGF-β1 increased expression and synthesis of both fibronectin and nerve growth factor (NGF), whereas dexamethasone stimulated fibronectin synthesis but inhibited NGF expression. The application of both TGF-β1 and dexamethasone resulted in an additional effect on fibronectin; however, dexamethasone inhibited the TGF-β1-induced NGF expression. Dexamethasone promotes fibronectin synthesis and suppresses NGF secretion, suggesting that this reagent could be used clinically to reduce pain and promote dental pulp tissue healing.