Immunohistochemical localization of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in human carious dentine

We evaluated if immunolocalization of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in odontoblast dentinal tubuli changes in response to caries attack in human carious teeth. Ten permanent premolar teeth with moderate to advanced caries and two sound teeth were collected. The premolars were decalcified in ethylene-diamininetetracetic acid (EDTA) and processed for embedding in paraffin wax. Sections of 3-4mum thick were cut and processed for immunohistochemistry. A mouse monoclonal anti-TIMP-1 antibody was used for the localization of TIMP-1 using an immunperoxidase technique. TIMP-1 immunoreactivity was observed in dentine of both sound and carious teeth. In both cases, the density of immunolabelled dentinal tubuli was typically higher toward the pulp chamber. In all the carious teeth, most, but never all, dilated dentinal tubuli were strongly positively immunolabelled. In sound teeth, a weak immunoreaction, only slightly above the background, was observed in dentinal tubuli. These results provide evidence for increased TIMP-1 immunolabelling in dentinal tubuli of carious teeth, in contrast to sound teeth. Overall, these in vivo findings indicate a possible role for TIMP-1 in the pathology of adult human dental tissues following an injury such as a caries lesion.