Immunohistochemical localization of bone sialoprotein, osteopontin and esteocalcin in periodontium

Objectives:Sialoprotein, osteopontin and esteocalcin are all secreted at different stages of osteogenic cell differentiation. They have a role in calcification of bone and cementogenesis. The purpose of this study was to investigate the distribution of bone sialoprotein, osteopontin and esteocalcin in periodontium by immunohistochemistry and identify cell populations within the periodontium that have the potential to produce mineralized matrices and hence the ability to regenerate bone and cementum within the periodontium. Methods:The second moler and its associated periodontium were extracted from an adult dog. The sample were fixed in 4% paraformaldehyde, decalcified in 10% EDTA, dehydrated in graded alcohols, cleared in n-butyl alcohol and embedded in paraffin. 5µm serial sections were used in this study. The immunostaining processes were carried out with SP method. Results:Osteopontin was positive in periodontal ligament cells and the matrix of the ligament, mild positive in alveolar bone and gingivae, negative in cementum; the staining of esteocalcin was the same as that of osteopontin; bone sialoprotein was positive in periodontal ligament, mild positive in alveolar bone and cementum, negative in gingivae. The results showed different expression of sialoprotein, osteopontin and esteocalcin in periodontal ligament, alveolar bone, cementum and gingivae. Conclusions: distinct differences of these proteins between the fibroblast populations suggest that they may be useful as markers of cells that have the potential for hard tissue formation and the ability to facilitate periodontal regenerarion.