ToxSci Advance Access originally published online on July 29, 2008
Toxicological Sciences 2008 106(1):214-222; doi:10.1093/toxsci/kfn156
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Tributyltin Impairs Dentin Mineralization and Enamel Formation in Cultured Mouse Embryonic Molar Teeth
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* Department of Pediatric and Preventive Dentistry, Institute of Dentistry, 00014 University of Helsinki, Helsinki, Finland
Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki, Finland
Department of Oral Pathology, Institute of Dentistry, 00014 University of Helsinki, Helsinki, Finland
Department of Pathology, Helsinki University Central Hospital, Helsinki, Finland
1 To whom correspondence should be addressed at Biomedicum Helsinki, Institute of Dentistry, University of Helsinki, PO Box 63, FI-00014 Helsinki, Finland. Fax: +358-9-1912-5371. E-mail: eija.peltonen{at}helsinki.fi.
Received May 16, 2008; accepted July 23, 2008
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Abstract |
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Tributyltin (TBT), earlier used as an antifouling agent in marine paints, causes damage to the aquatic ecosystem, for example, impaired shell calcification in oysters. TBT affects hard tissue mineralization even in mammals: delayed bone mineralization has been observed in rodents exposed to TBT in utero. To see if TBT interferes with tooth development, especially dental hard tissue formation, we exposed mouse E18 mandibular first and second molars to 0.1, 0.5, 1.0, and 2.0µM TBT chloride in organ culture for 7–12 days. The amount of enamel was assessed and the sizes of the first molars were measured from photographs taken after the culture. TBT concentration dependently impaired enamel formation (p < 0.001) and reduced tooth size (p < 0.001). Histological analysis showed slight arrest of dentin mineralization and enamel formation in first molars exposed to 0.1µM TBT. At the concentration of 1.0µM the effect was overt. The differentiation of ameloblasts in the mesial cusps was retarded but TBT had no effect on odontoblast morphology. The dental epithelium showed enhanced apoptosis. The failure of ameloblasts to form enamel was likely to be secondary to the effect of TBT on dentin mineralization. In the second molars, where predentin deposition had not started, ameloblasts and odontoblasts were nonpolarized and proliferative. The results showed that TBT concentration dependently impairs dental hard tissue formation and reduces tooth size in cultured mouse embryonic molars. The effects depend on the stage of tooth development at the start of exposure and may involve epithelial-mesenchymal interactions.
Key Words: Tributyltin; tooth development; dentin mineralization; enamel; apoptosis; mouse.