实时三维超声辐照对晚孕胎鼠大脑神经细胞凋亡的影响

目的 探讨不同实时三维超声辐照剂量对晚孕胎鼠大脑神经细胞凋亡的影响.方法 30只孕鼠随机等量分配到对照组、假辐照组、辐照5 min、10 min、20 min及30 min组.辐照组在孕鼠孕16 d时行实时三维超声辐照.每组选生后24 h乳鼠2只,取大脑右侧顶叶做标本,透射电镜下观察.其余乳鼠于生后10 d行灌流固定,取大脑标本,HE染色光镜观察及原位末端标记(TUNEL)法检测凋亡大脑细胞.结果 光镜结果:对照组、假辐照组、辐照5 min组及辐照10 min组光镜观察未见明显异常,辐照20 min组及30 min组,神经细胞排列紊乱,部分神经细胞坏死.TUNEL法标记结果:辐照5 min组凋亡细胞表达率与对照组和假辐照组间比较差异无统计学意义;辐照10 min组凋亡细胞开始增多,辐照20 min、30 min组凋亡细胞表达率明显增强,与其他各组相比差异具有统计学意义.电镜结果:对照组、假辐照组、辐照5 min组未见明显异常;辐照10 min组可见部分线粒体膨大,嵴断裂,内质网呈空泡化,偶见凋亡细胞;辐照20 min、30 min组线粒体与粗面内质网异常改变增多,凋亡细胞明显增多.结论 实时三维超声辐照超过10 min可引起大脑神经细胞形态改变和凋亡细胞增加.

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

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.