N. Shigemura et al., Localization of activated caspase-3-positive and apoptotic cells in the developing tooth germ of the mouse lower first molar, HISTOCHEM J, 33(5), 2001, pp. 253-258
This study examined the immunohistochemical detection of activated caspase-
3, and its association with apoptosis, during tooth morphogenesis of the mo
use lower first molar. The distribution of cells positive for caspase-3 clo
sely corresponded with the localization of the terminal deoxynucleotidyl tr
ansferase-mediated deoxyuridine-5'-triphosphate-biotin nick end labelling (
TUNEL)-positive apoptotic cells through the developmental course of tooth g
erms from embryo day 12 (E12) to E19, thus showing that the apoptosis occur
ring in the developing odontogenic tissue was induced by the activation of
the caspase family. The specific distribution pattern of apoptotic cells in
the developing odontogenic epithelial tissue from the initiation (E12) of
tooth germ to the completion of tooth crown morphology (E19) also suggests
that apoptotic events are related not only to a deletion of functionally su
spended cells, but also participate in initiation and the completion of too
th morphogenesis. Electron microscopic examination revealed that apoptotic
cells were present in the primary enamel knot, and these apoptotic cells we
re phagocytized by neighbouring odontogenic epithelial cells, thus indicati
ng the prompt disposal of any dead cells by epithelial cells.