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Programmed cell death in the development of the mouse external auditory canal
K Nishizaki1, M Anniko, Y Orita
1Department of Otorhinolaryngology, Okayama University Medical School, Japan. nishizak@cc.okayama-u.ac.jp
The Anatomical Record
|November 12, 1998
Summary
Programmed cell death (PCD), or apoptosis, is crucial for external auditory canal (EAC) development. This study found PCD involved in epithelial plate formation, not EAC recanalization.
Area of Science:
- Developmental Biology
- Cell Biology
- Otolaryngology
Background:
- Programmed cell death (PCD) is vital for embryonic development.
- Apoptosis plays a role in tissue morphogenesis and remodeling.
Purpose of the Study:
- To investigate the role of PCD, specifically apoptosis, in the development of the external auditory canal (EAC).
- To determine the temporal and spatial distribution of apoptosis during EAC formation in mice.
Main Methods:
- Time-sequence study using ICR mice from embryonic day 11.5 to 12 days after birth.
- Morphological analysis via light and electron microscopy.
- Histochemical detection of apoptosis using the TUNEL method.
Main Results:
- Apoptosis was observed in the branchial arch on E11.5.
- TUNEL-positive cells were abundant in the EAC between E15.5 and 1 day after birth, decreasing with age.
- Apoptosis occurred during epithelial plate formation but not during EAC recanalization, except for skin terminal differentiation.
Conclusions:
- PCD (apoptosis) is essential for the formation of the epithelial plate during EAC development.
- Recanalization of the EAC is associated with epithelial cornification, not apoptosis.