An organotypic in vitro model that mimics the dento-epithelial junction.
BACKGROUND
The dento-epithelial junction forms the primary periodontal defense structure against oral microbes. The cells of the junctional epithelium (JE) attach both to a basement membrane (BM) facing the connective tissue and to a hard dental tissue by structurally similar but molecularly distinct mechanisms. Here we describe a new organotypic cell culture model for the dento-epithelial junction comprising not only epithelial and mesenchymally derived components, but also a tooth surface equivalent.


METHODS
Rat palatal keratinocytes were seeded on fibroblast-collagen gels. A tooth slice was placed on top of the epithelial cells and the multilayer cultures were grown at the air-liquid interface. Formation of the epithelial structures, BM components, and the epithelial attachment to the tooth surface were studied by immunofluorescence and light and electron microscopy. The findings were compared to the structure of the dento-epithelial junction in vivo.


RESULTS
A well-differentiated stratified epithelium was formed. Under the tooth slice the epithelium remained thin and non-differentiated. Attachment of the epithelial cells to the tooth surface was mediated by hemidesmosomes (HDs) as in vivo. Laminin-5 (Ln-5) was present in the extracellular matrix (ECM) between the tooth and the epithelium as well as in the BM structure between the epithelium and the fibroblast-collagen matrix. Instead, Ln-10/11 was present only at the mesenchymal tissue side as is known to be the case in vivo.


CONCLUSIONS
The organotypic model presented expresses the characteristic structural and molecular features of the dento-epithelial junction and may be applied for studying physiological and pathological processes in the epithelial attachment.
Oksanen
Jaana
J
Department of Periodontology, Institute of Dentistry, University of Turku, Finland. jaana.oksanen@utu.fi
Hormia
Marketta
M
D000818:Animals; D001485:Basement Membrane / Q000033:anatomy & histology / Q000166:cytology; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000648:ultrastructure; D003094:Collagen / Q000648:ultrastructure; D003238:Connective Tissue / Q000033:anatomy & histology; D004846:Epithelial Attachment / Q000033:anatomy & histology* / Q000166:cytology; D004847:Epithelial Cells / Q000166:cytology; D004848:Epithelium / Q000033:anatomy & histology; D005109:Extracellular Matrix / Q000648:ultrastructure; D005347:Fibroblasts / Q000166:cytology; D005455:Fluorescent Antibody Technique; D022002:Hemidesmosomes / Q000648:ultrastructure; D006801:Humans; D015603:Keratinocytes / Q000166:cytology; D007797:Laminin / Q000648:ultrastructure; D008648:Mesoderm / Q000166:cytology; D008854:Microscopy, Electron; D023421:Models, Animal; D009924:Organ Culture Techniques; D051381:Rats; D017208:Rats, Wistar; D014070:Tooth / Q000033:anatomy & histology*; D000097794:Kalinin
D015815:Cell Adhesion Molecules; D003094:Collagen; D007797:Laminin; D000097794:Kalinin; C119013:laminin 10