Intercellular Junctions Between Human Odontoblasts

Background Mature odontoblasts possess junctional structures constituted by adherens, gap, and tight junctions. Although adherens and gap junctions appear early between odontoblasts, there is no information on the appearance and development of tight junctions between odontoblasts. In this study, we have examined freeze‐fracture replicas of early dentinogenesis to study the development of tight junctions between odontoblasts and to determine whether these junctions are of zonular or macular type. Methods Upper first molar tooth germs of Wistar rats between 1 and 3 days old were fixed in buffered 4% glutaraldehyde/4% formaldehyde and subsequently cryoprotected with cacodylate‐buffered glycerol. Freeze‐fracture replicas were obtained in a Balzers 301 apparatus, and early stages of dentinogenesis were examined in a Jeol 100 CX II electron microscope. Results In the stage of early dentine matrix prior to mineralization, odontoblasts exhibit only gap junctions. With the progression of development, the distal plasma membranes of odontoblasts show numerous short tight junctions formed by fused particles and grooves. In the stage of advanced mineralization, branched and continuous rows of fused particles or grooves constitute tight junctions of the focal or macular type. Conclusions The present study shows that tight junctions of focal or macular type appear on distal plasma membrane of early odontoblasts during differentiation. Formation of tight junctions indicates the establishment of a distal membrane domain and maturation of odontoblasts. These events occur as mantle dentine formation ceases and circumpulpar dentine formation begins. Anat. Rec. 248:332‐338, 1997. © 1997 Wiley‐Liss, Inc.

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Tight junctions in differentiating ameloblasts and odontoblasts differentially express ZO‐1, occludin, and claudin‐1 in early odontogenesis of rat molars

João

Arana-Chavez

2004

Anat. Rec.

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Little is known about the expression of associated proteins during the assembly of tight junctions (TJs). We studied the distribution of ZO-1, occludin, and claudin-1 between differentiating ameloblasts and odontoblasts in molar tooth germs from 1-to 3-day-old rats by confocal laser scanning microscopy. Immunoreactivity for ZO-1 was strong at proximal and distal junctional complexes of differentiating ameloblasts, while it was weak and punctuate at the distal region of differentiating odontoblasts. Occludin was immunoreactive at distal and proximal complexes of early differentiating ameloblasts and at distal regions of differentiating odontoblasts. However, in more advanced stages, occludin was only evident at the proximal complex of ameloblasts. Claudin-1 was strongly detected at the proximal complex but it was weak at distal complex of late differentiating ameloblasts. Thus, our results showed that ZO-1, occludin, and claudin-1 are differentially expressed as TJs assemble for regulating polarity and/or paracellular permeability in differentiating ameloblasts and odontoblasts. Anat Rec Part A 277A: 338 -343, 2004.

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Intercellular Junctions Between Human Odontoblasts

Cited by 26 publications

References 20 publications

Structure and organization of odontoblasts

Structure and organization of odontoblasts

Development of tight junctions between odontoblasts in early dentinogenesis as revealed by freeze-fracture

Tight junctions in differentiating ameloblasts and odontoblasts differentially express ZO‐1, occludin, and claudin‐1 in early odontogenesis of rat molars

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