Effects of prenatal irradiation on the development of cerebral cortex and corpus callosum of the mouse
Defects of the cerebral cortex and corpus callosum of mice subjected prenatally to gamma irradiation were evaluated as a function of dose and of embryonic age at irradiation. Pregnant mice were exposed to a gamma source at 16, 17, and 19 days of gestation (E16, E17, and E19, respectively), with total doses of 2 Gy and 3 Gy, in order to produce brain defects on their progeny. At 60 postnatal days, the brains of the offspring were analyzed qualitatively and quantitatively and compared with those of nonirradiated animals. Mice irradiated at E16 were all acallosal. Those that were exposed to 2 Gy displayed an aberrant longitudinal bundle typical of other acallosals, but this was not the case in those irradiated with 3 Gy. The corpus callosum of animals irradiated at E17 with 3 Gy was pronouncedly hypotrophic, but milder effects were observed in the other groups. Quantitative analysis confirmed a dependence of callosal midsagittal area upon dose and age at irradiation, and, in addition, indicated an interaction between these variables. The neocortex of irradiated animals was hypotrophic: layers II-III were much more affected than layer V, and this was more affected than layer VI. Quantitative analysis indicated that this effect also depended on dose and age at irradiation and that it was due to a loss of cortical neurons. Furthermore, a positive correlation was found between the number of neurons within layers II-III, and V and the midsagittal area of the corpus callosum. Ectopic neurons were found in the white matter and in layer I of animals irradiated at E16 and E17, indicating that fetal exposure to ionizing radiation interfered with the migration of cortical neuroblasts.
- Research Organization:
- Universidade Federal do Rio de Janeiro, Cidade Universitaria, Brazil
- OSTI ID:
- 5602400
- Journal Information:
- J. Comp. Neurol.; (United States), Vol. 264:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BRAIN
BIOLOGICAL RADIATION EFFECTS
GAMMA RADIATION
TERATOGENESIS
AGE DEPENDENCE
CEREBRAL CORTEX
EMBRYOS
MICE
PREGNANCY
PRENATAL EXPOSURE
PROGENY
RADIATION DOSES
ANIMALS
BIOLOGICAL EFFECTS
BODY
CENTRAL NERVOUS SYSTEM
CEREBRUM
DOSES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
MAMMALS
NERVOUS SYSTEM
ORGANS
RADIATION EFFECTS
RADIATIONS
RODENTS
VERTEBRATES
560152* - Radiation Effects on Animals- Animals