Epithelial and ED1 immunopositive cells in rat PDL

Title : Immunohistochemical localization of Epithelial cell rests of Malassez and ED1 immunopositive cells in rat periodontal ligament

Authors:Tadokoro O, Kawahara I, Vandevska-Radunovic V, Inoue K

Objectives: Our previous immunohistochemical and immunoelectron microscopic analyses have verified the presence of neuroendocrine cells in both human and cat epithelial cell rests of Malassez (ERM) and also OX6 immunopositive cells in rat ERM. The intimate relation between the rat ERM and the OX6 immunopositive cells indicates a functional diversity of ERM in rat periodontal ligament (PDL).

The present study analyzed the distribution and the co-localization of the immunocompetent cells and ERM in normal rat PDL, using a double immunofluorescence microscopy.

Materials and Methods: Seven male mol:WIST rats, approximately 170g in weight were anesthetized and perfused with 4% paraformaldehyde. The maxillas were excised and postfixed in the same fixative. After demineralization in EDTA, sagittal 7-8 µm thick serial sections were cut in a cryostat. The sections were immunolabelled with cytokeratin (CK) polyclonal and ED1-monoclonal antibodies and analyzed and photographed in a fluorescence microscope.

Results: CK-immunopositive ERM were distributed mainly in the cervical and furcational PDL. Some sections showed CK-immunopositive ERM in the apical region and in the alveolar bone lacunae facing the furcation area. ED1-immunopositive cells were distributed throughout the PDL, gingiva and the alveolar bone. Few sections demonstrated co-localization of ERM and ED1-immunopositve cells in the PDL and the alveolar bone lacunae.

Conclusions: This study revealed co-localization of ERM and ED1-immunopositve cells in the rat periodontium, indicating a functional relationship between these two cell types.

This study was supported by a Grant-in Aid for Scientific Research from the Ministry of Education, Science, Sports, and Culture, Japan (19791356).