Effect of diagnostic live three-dimensional ultrasound on apoptosis of embryo-cerebral cells in late pregnant mice

Abstract

Objective To study the effect of live three-dimensional ultrasound aniso-irradiation on apoptosis of embryo-cerebral cells in late pregnant mice.Methods Thirty pregnant mice were randomly divided into 6groups,unexposed group,pseudo-exposed group,5 min-exposed group,10 min-exposed group,20 min-exposed and30 min-exposed group,5 mice in each group.Exposed mice were irradiated under the system's probe for 5 to 30 min on pregnant day 16.Two fetuses of each group 24h after birth were selected,the right parietal lobes were observed with transmission electron microscope.On the 10th day after birth,the other fetuses of each group were perfused and fixed with 4% paraformaldehyde,brain slices were made and stained with HE or terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL).Results 1)Light microscope:there were no evident abnormal changes in unexposed group,pseudo-exposed group,5 min-exposed group and 10 min-exposed group.The disorder of nerve cell arrangement and cell necrosis were observed in 20 min-exposed group and 30 min-exposed group.2)Tunel method:comparing with un-exposed group and pseudo-exposed group,positive rate of apoptosis in 5 min-exposed group had no significant statistically difference(P>0.05).but in 10 min-exposed group,apoptosis positive cells were increased and the findings became remarkable in 20 min-exposed and 30 min-exposed groups which showed a significant statistically difference(P<0.01)compared with other four groups.3)Electron microscope:there were no obvious abnormal changes in unexposed group,pseudo-exposed group,and 5min-exposed group.There were some mitochondrion enlargement,crista breakage,vacuolization of rough endoplasmic reticulum and a few apoptosis cell were seen in 10 min-exposed group.More abnormal mitochondrion,rough endoplasmic reticulum and apoptosis cells were observed in 20 min-exposed and 30 min-exposed groups.Conclusions Live three-dimensional ultrasound irradiation for more than 10 minutes may result in abnormal neuron morphological changes and apoptosis in fetal mouse cerebrum. Key words: Ultrasonography; Mice; Neurons; Apoptosis