Behavioral changes and structural defects in rats irradiated in utero.
Pregnant rats were irradiated with whole-body doses (0.25-1.25 Gy) of Cs-137 gamma-rays on gestational day 15, or with 1.0 Gy on gestational days 11, 13, 15, or 17. Postnatal growth (body weight) and several preweaning behaviors (righting reflex, negative geotaxis, reflex suspension, modified open field activity, spatial maze exploration, continuous corridor activity, and gait) of the offspring were monitored prior to sacrifice on post-parturition day 28. Brain (sensorimotor cortex) and pituitary tissues were processed for histological evaluation and morphometric analysis. For most behavioral endpoints, there were dose-dependent changes produced by irradiation on gestational day 15, with one endpoint (continuous corridor activity) demonstrating changes after 0.25 Gy that were significantly different from control values. The data indicate that the most sensitive organ showing radiation-induced alterations changes from the pituitary at gestational day 11 to the primitive cortex of the brain at days 13 to 17 with a peak of sensitivity at day 15. These results demonstrate that a spectrum of related functional and morphological deficits can be produced by even low-dose in utero irradiation, with the specific endpoint showing the greatest change being determined by the specific day of gestation on which irradiation occurs. Extrapolating from these experimental data with rats to the human situation, it is recommended that care be taken, when possible, to avoid exposure of the fetus, even after the early stages of organogenesis.
Kimler
B F
BF
Department of Radiation Oncology, University of Kansas Medical Center, Kansas City 66103.
Norton
S
S
D000818:Animals; D001522:Behavior, Animal / Q000528:radiation effects*; D001835:Body Weight / Q000528:radiation effects; D005260:Female; D005333:Fetus / Q000528:radiation effects*; D005865:Gestational Age; D008297:Male; D010902:Pituitary Gland / Q000528:radiation effects; D051381:Rats; D013003:Somatosensory Cortex / Q000528:radiation effects