In vitro immunoexpression of extracellular matrix proteins in dental pulpal and gingival human fibroblasts.
OBJECTIVE
To compare the expression of extracellular matrix (ECM) components in human pulpal and gingival fibroblasts in vitro.


METHODS
Cultured dental pulp fibroblasts and gingival mucosa fibroblasts were used. Tenascin (TN), fibronectin (FN), type I (col I) and III collagen (col III) and osteonectin (ONEC) were detected by immunofluorescence. Main morphological characteristics were also analysed by light microscopy (LM) and transmission electron microscopy.


RESULTS
The results revealed different expression patterns of the proteins. TN and ONEC were only immunoexpressed by pulpal fibroblast cells, suggesting a role of these glycoproteins in formation of mineralized tissues. FN and col I were present in the cytoplasms of both cell types. No expression of col III was detected. Different morphological characteristics were visualized under LM, in which pulpal fibroblasts were spindle-shaped with a wide cytoplasm, while gingival fibroblast cells exhibited stellate/pyramidal configuration, with rounded nuclei. However, ultrastructurally, both cell lineages showed very well developed rough endoplasmatic reticulum and Golgi complex.


CONCLUSIONS
Due to the immunodetection of TN and ONEC on pulpal fibroblasts, the present findings demonstrated that a pulpal fibroblast cell is similar to an osteoblastic cell rather than an undifferentiated mesenchymal cell, such as a gingival fibroblast cell. Functional differences between the two cell lines may then be suggested.
Department of Oral Pathology, Faculty of Dentistry, University of São Paulo, 00508-900 São Paulo, Brazil. efmartinez@ig.com.br
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Martinez
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Araújo
D019070:Cell Lineage; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis; D024061:Collagen Type III / Q000096:biosynthesis; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000096:biosynthesis; D005455:Fluorescent Antibody Technique; D005881:Gingiva / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D015676:Osteonectin / Q000096:biosynthesis; D019063:Tenascin / Q000096:biosynthesis
D024042:Collagen Type I; D024061:Collagen Type III; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D015676:Osteonectin; D019063:Tenascin