Immunolocalization of bone extracellular matrix proteins (type I collagen, osteonectin and bone sialoprotein) in human dental pulp and cultured pulp cells

Aim To simultaneously analyse the expression of type I collagen, osteonectin and bone sialoprotein (BSP) in human dental pulp of different ages. Methodology Cultured dental pulp fibroblasts (FPI cell line), pulps from dental germs with incomplete root formation (n = 4) and pulps of erupted teeth with total root formation (n = 4) were used. Bone proteins were searched by immunohistochemistry and immunofluorescence using polyclonal antibodies and compared among the three groups assessed. Results Immunohistochemistry detected the three proteins in dental pulp tissue, as it labelled extracellular matrix, predentine and odontoblasts. The BSP label was weal;er, when compared to both type I collagen and osteonectin. The presence of type I collagen was more evident in pulps from erupted teeth, when compared to germ dental pulps. On the other hand, a strong expression of osteonectin in germ dental pulps was observed. Conclusions Regardless of the degree of maturation, dental pulps present type I collagen, osteonectin and BSP in the extracellular matrix (ECM) and in the odontoblastic layer. Thus, the results suggest that these proteins are related to the production and mineralization of dentine.