Immunohistochemical localization of matrixmetalloproteinase-2 in human coronal dentin

While it is known that matrixmetalloproteinase-2 (MMP-2) is present in dentin, its distribution and role in human dentin formation and pathology are not well understood. Objective To characterize the distribution of MMP-2 in human coronal dentin. Methods Immunohistochemistry was used to investigate the distribution of MMP-2 in coronal dentin. Freshly extracted human premolars and third molars (age range 12–30) were fixed with formaldehyde, demineralized with 10% EDTA (pH 7.4) and embedded in paraffin. Serial sections were made and subjected to immunohistochemical analysis using a specific monoclonal anti-MMP-2 antibody. Immunoreactivity was visualized with 3,3′-diaminobenzidine substrate and observed under light microscopy. ImageJ software was used to calculate the relative amount/distribution of MMP-2. Results The analysis revealed immunoreactivity for MMP-2 throughout human coronal dentin. However, intense immunoreactivities were identified in a 90–200 μm zone adjacent to the pre-dentin as well as a 9–10 μm wide zone adjacent to the dentinoenamel junction (DEJ). Conclusion MMP-2 has a specific distribution in human coronal dentin indicating itʹs involvement in extracellular matrix organization in predentin and the establishment of the DEJ.