Time-sequenced alteration of immunolocalization and significance of Notch-2 expression in rat pulpitis / 实用口腔医学杂志

ABSTRACT

Objective; To investigate the immunolocalization and significance of Notch-2 expression in the process of dental pulp repair after injury. Methods: An experimental animal model of injury-induced pulpitis was established to observe the time-sequenced alteration of the expression of Notch-2. Results: Three days post-operation, weak positive staining of Notch-2 was observed in pulp mesenchyme cells and pulp fibroblasts but not in vascular endothelial cells or odontoblasts. Five days post-operation, strong Notch-2 reactivity was found in subodontoblasts as well as newly bom capillary endothelial cells. Seven days after cavity preparation, Notch-2 staining became weaker in pulp mesenchyme cells and capillary endothelial cells, but stronger positive staining was found in odontoblasts. Two weeks post-operation, weak Notch-2 staining was seen in pulp mesenchyme cells and subodontoblastic layer cells and was absent from odontoblasts. Notch-2 immunoreactivity was completely absent in intact rat dental pulp. Conclusion: Notch-2 is strikingly up-regulated in dental pulp mesenchyme cells in the early days after dental injury and then shows progressively up-regulation in odontoblasts. Properly regulated activation of Notch signaling pathway is important for controlling cell fate and maintaining the correct balance among cell proliferation, differentiation and apoptosis during dental pulp repair process.