-Abstract-
Early tooth development is a complex and timed process including cellular
proliferation, differentiation. epithelial-mesenchymal interaction and mineralization. Bone
morphogenetic proteins are known to be an important signaling molecule in the tooth
morphogenesis. In this study, I investigated the expression pattern and possible role of
BMP-2 and BMP-4 in the developing tooth of rats by immunohistochemistry.
The results are as follows :
1. In embryonic 15 days, the tip of proliferating epithelial tooth bud shows stronger
immunoreactivity for BMP-2. Epithelial layer of tooth bud facing oral epithelium shows
stronger immunoreactivity than others for BMP-4.
2. In embryonic 18 days, moderate immunoreactivity is shown on stratum intermedium
at the center of dental organ for BMP-2 and BMP-4. Internal dental epithelium and
dental papilla show weak immunoreactivity for BMP-2 and BMP-4.
3. In embryonic 20 days, dental organ is stained weak and dental follicle is moderate for
BMP-2. Dental follicle and stratum intermedium are moderately stained for BMP-4.
Bone cells on surface and in lacunae of developing alveolar bone show strong
immunoreactivity for BMP-2 and BMP-4.
4. In postnatal 3 days, both for BMP-2 and BMP-4, secretory odontoblasts show strong
immunoreactivity, but as differentiation is advanced, expression on odontoblasts
disappearas and ameloblasts begin to be stained at their distal cytoplasm.
These results suggest that BMP-2 and BMP-4 may have a role to guide the cell
proliferation, differentiation and matrix secretion during early tooth development.
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