OBJECTIVEDeveloping mouse molar was used as a model for the study of Syndecan-1, a transmembrane heparan sulfate proteoglycans, in order to approach the possible mechanism and function of this macromolecule during tooth development.

METHODSMouse embryos were removed at different days of gestation. The frozen sections of the first lower molar were made from the embryonic mouse heads and then indirect immunofluorescence was performed on these sections. The altered distribution pattern of Syndecan-1 in embryonic mouse first lower molars at different stages of development from the bud to the late bell stage was observed under a conventional fluorescence microscope.

RESULTSThere was a ubiquitous staining in the dental tissues at bud stage: Both the epithelium and mesenchyme were weakly positive for Syndecan-1. From the bud to the cap stage, there was a strong decrease of the staining for Syndecan-1 in the epithelial compartment, while an intense staining in dental mesenchyme was observed at cap stage. At bell stage, Syndecan-1 was again detected in dental epithelium including the stratum intermedium and the outer enamel epithelium, and it was found having some intense signal in the stratum intermedium. However, the staining for Syndecan-1 in dental mesenchyme of this stage became weaker and finally disappeared. Furthermore, a positive expression for Syndecan-1 was also found at the top of pre-ameloblasts as well as odontoblasts.

CONCLUSIONThese changes in the patterning of Syndecan-1 during tooth development might be related with cell proliferation during morphogenesis and later be involved in the differentiation of ameloblast and odontoblast.