Beschreibung:
Objective: Propylthiouracil (PTU) is originally a thiouracil‐derived drug used to treat hyperthyroidism by blocking the effect of thyroid hormone. Recently, PTU is using as a marker of pollutant as a potential thyroid hormone disruptor in aquatic environments. The purpose of this study was to evaluate the effects of exposure to PTU on the development of the teeth and the regeneration of alveolar bone following amputation.Method: Japanese newts (Cynops pyrrhogaster) were maintained in aqueous solutions with or without 100 ug/ml PTU for one month and tracked the sequential development of the tooth cap, the tooth bud, and ultimately the maturation of the sequential tooth germ. Fifty days after the amputation procedure of the right mandible alveolar bone, the newts were observed the effect of PTU by the expression levels of mRNA of thyroid hormone receptor detected in‐situ hybridization. A microscope and digital camera interfaced with Image Analysis & Measurement Software WinROOF (Mitani Corp., Japan) were used to measure the areas of regenerated alveolar bone.Result: The amputated mandible sites were observed microscopically. The regenerated area of alveolar bone in amputation with PTU treatment was significantly smaller than that in the amputation without PTU treatment (Student’s t‐test, p<0.001). There were no differences in the bone histology and tooth germ generation with or without PTU.Conclusion: These data indicate that PTU may affect the tooth germ development and the regeneration of alveolar bone in newts.