Expression of the junctional proteins connexin 43 and ZO-1 in differentiating ameloblasts, odontoblasts and osteoblasts in tooth germs and alveolar bone from rat molars

Abstract

We studied the distribution of Cx43 and ZO-1 by confocal laser scanning microscopy at early stages of amelogenesis and dentinogenesis in tooth
germs and osteogenesis in alveolar bone from rats. Cx43 was detected at the distal and medial regions of undifferentiated ameloblasts, between cells from stratum intermedium and stellate reticulum. Differentiating odontoblasts exhibited immunoreaction at their distal end. ZO-1 was observed at proximal and distal junctional complexes of ameloblasts; in the odontoblasts was present at apical regions, with punctate appearance. In more advanced stages, expression of Cx43 was more intense on ameloblasts and odontoblasts in the same area. Immunoreaction for ZO-1 in ameloblasts was stronger than that the previous stage in ameloblasts, in their junctional complexes as well as in odontoblasts in
their distal area. In the alveolar bone, Cx43 was present in osteoblasts and osteocytes and/or cell processes. The ZO-1 was detected in the osteoblast surface. This study showed that differentiating ameloblasts, odontoblasts and osteoblasts start to express Cx43 and ZO-1 as early as
their differentiation process begins.