【作者】 周宁；

【导师】 段云友；

【作者基本信息】 第四军医大学 ， 影像医学与核医学， 2008， 博士

【摘要】 目的彩色多普勒超声检查已成为产前检查的一项重要手段。发育中的胎脑对超声非常敏感,已有研究表明孕期彩色多普勒超声照射后可引起脑组织细胞凋亡以及超微结构的变化,但是凋亡和超微结构的变化是否会影响子代的脑功能,目前尚无系统性研究。本实验旨在探讨孕期诊断剂量彩色多普勒超声辐照孕鼠子宫投影区一定时间,是否对仔鼠脑功能产生影响,以及观察海马区超微结构的变化,从而为彩色多普勒超声的产科安全应用提供有价值的实验依据。方法通过观察阴栓及镜检活精子,结合触诊胎囊大小的方法,成功获得孕6d,12d,18 d SD大鼠作为早、中、晚孕模型。各孕期孕鼠按照辐照时间随机分为4组:10min,20min,30min组和假辐照组。待其产下仔鼠后,仔鼠成长至90d,每组挑选健康仔鼠10只(体质量220-250g),先进行OF实验,之后进行Morris水迷宫测试。仪器采用Acuson公司Sequoia-512型彩色电脑声像仪,照射条件:4V1探头,二维频率H3.0 MHz,彩色频率3.0 MHz,Tis=1.8,MIcd=1.6。实验各组仔鼠生后90d分别进行开场实验(上海吉量软件科技有限公司研制的开场实验视频分析系统)及Morris水迷宫(上海吉量软件科技有限公司研制的全自动Morris水迷宫视频分析系统)测试。统计各组在开场实验中活动总路程、活动度、中央区时间、中央区路程以及平均运动速度以及在MWM实验中上台潜伏期及目标象限游泳时间的百分比。所得分数用统计软件spss 13.0进行评价。行为学实验后,取仔鼠脑组织进行HE染色及电子显微镜观察海马区超微结构的变化。结果开场实验中:与对照组相比,各孕期辐照10min,20min及30min组仔鼠的活动总路程、活动度、中央区时间、中央区路程以及平均运动速度均无明显差异(P>0.05)。MWM实验中:与对照组(10.78±3.89,37.42%±2.37%)相比,各孕期接受辐照30min组(21.96±5.29)仔鼠的上台潜伏期明显延长(P<0.05),目标象限游泳时间的百分比(27.89%±2.14%)显著降低(P<0.05);而10min(9.98±2.12,37.42%±1.89%)和20min(12.23±2.56,34.11%±2.65%)组与对照组相比则无明显差异(P>0.05)。光镜与电镜观察结果发现辐照组与对照组仔鼠海马区神经细胞超微结构并无明显差异。结论各孕期诊断剂量彩超照射对仔鼠的自发活动不产生明显影响。然而各孕期30min彩色多普勒超声照射虽然形态学上对仔鼠的神经细胞并未造成影响,但在功能上可能对仔鼠的学习记忆能力产生影响。因此产科检查时,建议应当避免对胎儿的长时间照射。更多还原

【Abstract】 Objective The safety of diagnostic ultrasound is an arising important topic in medical research. Therefore, the possibility of diagnostic CDUS causing adverse effects on fetal brain functions is an important but little-studied question. Most research focuses on the molecular level or examines the brain’s microstructure, while experimental studies on function are almost nonexistent. The intent of this study is to begin to bridge that gap. The objective of this experiment is to study the effect of color Doppler ultrasound (CDUS) during different durations of pregnancy on offspring’s brain functions and ultrastructure of hippocampus in rats.Methods Pregnant Sprague-Dawley(SD) rats were randomly divided into four groups according to the exposure time: control group (0 min group), 10 min group , 20 min group and 30 min group, and were exposed to ultrasound (3.0MHz, MI=1.6, Tis=1.8) differently on 6th, 12th, and 18th days of gestation. In each group, neonatal rats were selected to open field test for locomotion activity and then to Morris water maze test for learning and memory abilities at ninety days old. Then morphology of hippocampus was observed by transmission electron microscope.Results In the open field test, to the total distance,average velocity,activity,central distance and central time ,there were no differences between the 10 min group,20min group ,30min and the control group(P>0.05).In the Morris water maze test ,the escape latencies of rats in 30min group(21.96±5.29) were significantly longer than those of the control group(10.78±3.89 )(P <0. 05), the ratio of time spent in the target quadrant in 30min group(27.89%±2.14%) were significantly lower than that of the control group(37.42%±2.37%); and there were no significant differences between the 10 min group (9.98±2.12,37.42%±1.89%),20min (12.23±2.56,34.11%±2.65%)and the control (10.78±3.89, 37.42%±2.37%)group(P>0.05).To the ultrastructure, there were no differences between the exposed group and the control group.Conclusions Color Doppler ultrasound during different durations of pregnancy doesn’t have any effect on offspring’ locomotion activity. While thirty-min exposures to CDUS in utero during different durations of pregnancy could adversely affect the learning and memorizing ability of the rat offspring, and the 10 min exposures had no demonstrable effect.更多还原