Objectives: To elucidate localization of OATs in developing human tooth germs.
Methods: Formalin-fixed human deciduous tooth germs of still borne and aborted fetuses obtained at the Peradeniya University Hospital were decalcified with EDTA and embedded in paraffin. Deparaffinized sections were processed for immunohistochemical localization of OATs and some enamel matrix proteins after antigen retrieval with TEG buffer.
Results: All the tooth germs examined in this study were in early secretory stage of amelogenesis. Distinct immunoreactions for OAT2 were shown to be located exclusively along the distal cell membranes of secretory ameloblasts where Tomes’ processes were developed. OAT3 was strongly positive in the distal membranes but also moderately positive along the lateral membranes of secretory ameloblasts. Not all but large number of OAT-positive ameloblasts showed significant immunoreactions for amelogenin in the cytosol. Cytosolic immunoreaction was not depicted with the antibodies against ameloblastin or enamelin.
Conclusions: These data indicated existence of OATs 2&3 in the distal/lateral cell membranes of secretory ameloblasts and suggested possible involvement of these transporters in cytosolic translocation of extracellularly processed fragments of amelogenins and thus resorption of enamel matrix proteins.
Supported in part by a JSPS Grant-in-Aid for Scientific Research (B) (24390408).