Effects of irradiation and methyl-triazene on craniofacial development in mouse embryos: a semiautomated morphometric analysis.
OBJECTIVE
The purpose of the present study was a 2D-semiautomated morphometric analysis of craniofacial growth in nuclear magnetic resonance imaged (NMRI) mouse embryos.


METHODS
The NMRI mouse embryos were exposed in utero to either a single dose of 2 Gy X-irradiation on day 9 of gestation (113 embryos) or to 1.5 mg methyl-triazene administered orally to their pregnant mothers on gestational day 10.5 (124 embryos). An additional group of 108 embryos was used as controls. Digitized pictures of embryos from gestational days 14 to 17 were taken in lateral right view using a video system. Landmarks were located and digitized for computerized analysis of growth changes in relation to developmental stages of the face.


RESULTS
The results revealed that the snout of control embryos lengthens during the developmental period considered. The snout of embryos previously submitted to methyl-triazene displayed micrognathia, and all treated fetuses exhibited macroscopic signs of microcephaly with a reduced mandible. The snouts of irradiated embryos appeared shortened at the 14-day stage and continued to shorten as development proceeded. A shortening of the midface was detected macroscopically in 83% of the cases.


CONCLUSIONS
The results of this morphometric analysis enabled us to trace the developmental progression of the induced dysmorphosis and to assess the differences compared with normal development.
Service de Chirurgie Maxillo-faciale, Cliniques Universitaires, Hôpital Erasme, Bruxelles, Belgique.
R
R
Glineur
S
S
Van Sint Jan
S
S
Louryan
C
C
Philippson
V
V
De Maertelaer
L
L
Evrard
M
M
Rooze
D000014:Abnormalities, Drug-Induced / Q000209:etiology*; D000016:Abnormalities, Radiation-Induced / Q000209:etiology*; D000284:Administration, Oral; D000818:Animals; D002508:Cephalometry; D003037:Cobalt Radioisotopes / Q000009:adverse effects; D005314:Embryonic and Fetal Development / Q000187:drug effects / Q000528:radiation effects; D005145:Face / Q000002:abnormalities* / Q000196:embryology / Q000528:radiation effects; D005147:Facial Bones / Q000002:abnormalities / Q000187:drug effects / Q000196:embryology / Q000528:radiation effects; D005260:Female; D005865:Gestational Age; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000002:abnormalities / Q000187:drug effects / Q000196:embryology / Q000528:radiation effects; D008431:Maternal-Fetal Exchange; D051379:Mice; D008831:Microcephaly / Q000139:chemically induced / Q000196:embryology / Q000209:etiology; D008844:Micrognathism / Q000139:chemically induced / Q000196:embryology / Q000209:etiology; D009666:Nose / Q000002:abnormalities / Q000187:drug effects / Q000196:embryology / Q000528:radiation effects; D010315:Particle Accelerators; D011247:Pregnancy; D011829:Radiation Dosage; D019275:Radiopharmaceuticals / Q000009:adverse effects; D012886:Skull / Q000002:abnormalities* / Q000187:drug effects / Q000196:embryology / Q000528:radiation effects; D014226:Triazenes / Q000009:adverse effects*; D014743:Videotape Recording
D003037:Cobalt Radioisotopes; D019275:Radiopharmaceuticals; D014226:Triazenes