Apoptosis seems to be the major process while surface and neural ectodermal layers detach during neurulation.
OBJECTIVE
The aim of this study is to demonstrate the process of detaching neural and surface ectodermal layers soon after the neurulation completes.


METHODS
Specific pathogen-free chicken egg embryos were used to investigate the neurulation procedure. Ten eggs were saved as controls. The other ten eggs were opened at the 30th hour of embryo development and cultured with Z-VAD-FMK (peptide caspase inhibitor) to investigate the results of the apoptosis inhibition. Embryos were placed and developed up to 48 h in the culture medium. To detect apoptotic cells between neural and surface dermal layers, immunoreactivity of p53 and terminal uridine deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay were used.


RESULTS
While the control group shows positive immunoreactivity of p53 and TUNEL-positive apoptotic cells at the site where the neural folds detach from the surface ectoderm, no TUNEL activity and no detachment were detected in the apoptosis-inhibited group.


CONCLUSIONS
As inhibition of apoptosis prevented the detachment of the neural and surface ectodermal layers from each other at the end of the neurulation, inhibition of apoptosis seemed to cause a considerable embryological error accounted for congenital dermal sinus tractus maldevelopment.
Selçuki
Mehmet
M
Department of Neurosurgery, Celal Bayar University School of Medicine, Manisa, Turkey. mselcuki@yahoo.com
Vatansever
Seda
S
Umur
Ahmet Sukru
AS
Temiz
Cuneyt
C
Sayin
Murat
M
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002642:Chick Embryo; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004475:Ectoderm / Q000166:cytology* / Q000187:drug effects / Q000196:embryology*; D047108:Embryonic Development / Q000187:drug effects / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D020287:In Situ Nick-End Labeling; D009474:Neurons / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D000590:Amino Acid Chloromethyl Ketones; D015853:Cysteine Proteinase Inhibitors; D016159:Tumor Suppressor Protein p53; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone