Canibalismo em fêmeas de camundongo swiss expostas à irradiação ionizante durante a prenhez: alterações morfológicas associadas

Abstract

Irradiated female Swiss mice presented unexpected cannibalistic behaviors during an experiment involving tests for operational memory and reference assessment. This finding is not mentioned in previous works, which lead us to a more detailed study of the incidence and the possible causes related to that abnormal behavior. One group of 31 pregnant Swiss mice was exposed to whole body ionizing irradiation of X-rays through a linear accelerator apparatus of 6 MeV electron photonic energy, presenting total absorbed dose of 3 Gy (300cGy). Those animals were randomly divided into two groups, one for the analysis of prenatal and another for postnatal periods, and they were compared to mice from control groups. The data indicate that irradiation did not induce stress, intoxication or endocrine changes in mothers, however, irradiated female showed a high incidence (86.67%) of cannibalism. Fetuses from irradiated mothers had a decreased body weight (1077.1 mg ± 152.6 n=16) (p< 0.001) when compared to the control group (1241.2 mg ± 64.2 n=15) and also presented 28.1% of hypo activity, together with desorganization of brain cortical laminar layers and decrease in neuronal population. It was observed that irradiation did not cause morphological changes in maternal ovaries, hypohpysis and brain. The fetal motor disturbance probably induced the observed cannibalistic behavior.