Methods: Axin2-lacZ reporter mice were used ranging from embryonic day 10.5-16.5, to identify the sites of canonical Wnt activity in tooth development. Dental pulp cells from Axin2-lacZ mice were extracted and cultured for up to 4 weeks and then stained with X-gal.
Results: At the thickening stage of tooth development Axin2 expression can be found in epithelium and mesenchyme in the outer layer of the developing mandible. At the bud stage expression can be identified in the developing enamel knots of the incisors and the molar tooth buds. At the cap stage expression can be seen in the dental epithelium of the incisors and it is clearly visible in the developing enamel knots of the molars.
Wnt positive cells were cultured from dental pulp and the number of cells were found to increase with time in culture and with the age of the teeth.
Conclusion: Canonical Wnt signalling is evident at different staging of tooth development, suggesting it plays multiple roles in tooth development. Wnt signalling is identified in cultured dental pulp cells, as changes with tooth age revealed. The role of Wnt activity in responses to tooth damage is under investigation.