Developmental malformations and intrauterine deaths in gamma-ray-irradiated scid mouse embryos.
OBJECTIVE
To examine the induction by radiation of developmental malformations and intrauterine deaths in severe combined immunodeficiency (scid) mice.


METHODS
The scid embryos, as well as those of C.B-17 control mice, were irradiated with graded doses of 60Co gamma-rays on gestation day 8.


RESULTS
Intrauterine deaths in scid mice increased with radiation dose, and their frequency was substantially higher than in C.B-17 mice. The LD50 for intrauterine death in scid mice was 0.58 Gy and 1.25 Gy in C.B-17 mice. In addition, after irradiation scid mice showed several types of developmental malformations, including meningoencephalocele, spina bifida, eye defects, tail defects and oedema. Malformation incidences were higher in scid than in C.B-17 mice: 33.3% in scid mice irradiated with 0.75 Gy and 13.0% in C.B-17 mice irradiated with 1.0 Gy. However, when malformation incidences were plotted against intrauterine deaths, all the data, irrespective of the type of mouse, essentially fell along a single straight line.


CONCLUSIONS
These results suggest that some mechanism common to both scid and normal mice induces developmental malformations. This mechanism involves cell killing. Residual DNA damage, such as double-strand breaks, could be associated with radiation-induced teratogenesis.
Department of Environment and Mutation, Research Institute for Radiation Biology and Medicine, Hiroshima University, Japan.
S
S
Shoji
H
H
Watanabe
O
O
Katoh
Y
Y
Masaoka
S
S
Matsuura
H
H
Tauchi
S
S
Endo
K
K
Komatsu
D000016:Abnormalities, Radiation-Induced; D000818:Animals; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005313:Fetal Death; D005720:Gamma Rays; D007928:Lethal Dose 50; D008098:Litter Size / Q000528:radiation effects; D051379:Mice; D008815:Mice, Inbred Strains; D016513:Mice, SCID; D011247:Pregnancy; D013045:Species Specificity