Effects of 2,3,7,8-TeCDD during pregnancy on the neurodevelopment of rat fetuses and off-springs

孕期2,3,7,8-TeCDD对大鼠胎儿及子代神经发育的影响

• 批准号: 15590525
• 负责人: NISHIJO Muneko
• 金额: $ 1.92万
• 依托单位: KANAZAWA MEDICAL UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15590525/
• 关键词: Dioxin; fetus; off-spring; learning; motor development; neurodevelopment; behavior; brain; 運動; 大脳

The effects of 2,3,7,8-TeCDD (TeCDD) during pregnancy on motor development and learning processes of rat off-springs were investigated in this study.TeCDD or corn oil was orally administered to pregnant rats during the 9^<th> - 19^<th> day of pregnancy. Both of exposed and control off-springs were fed with ad libitum access to maternal breast milk after birth, and to food and water after weaning. The following experiments were conducted and obtained the results.1. Effects of TeCDD on fetus brain : On day 19 of gestation, fetuses of 6 TeCDD group and 5 controls were removed from the uterus. Brains were collected from the fetuses and divided into three parts : the cerebrum, cerebellum, and hypothalamus. The rates of hypothalamus per whole brain of TeCDD group were significantly higher than those of controls.2. Effects of TeCDD on off-springs : From the 4^<th> to 14^<th> day after birth, measurement the time of turning around on the slope was performed to test motor development. The latent time of TeCDD group was significantly longer than that of controls during the 7^<th> to 11^<th> day in both sexes. Every day from the 31^<th> to 44^<th> day after birth, performance of avoidance behavior in a shuttle box was examined after conditioning with a tone and electric shock. Improvement of escape rates and escape latent periods during these days was delayed in TeCDD group as compared with that of controls in male rats. Also lower spontaneous activity was observed in TeCDD exposed male rats. The increased rates of hypothalamus per whole brain of TeCDD group were also recognized in anatomical investigations after behavior examinations.These results suggest that TeCDD exposure during pregnancy affect neurodevelopment of off-springs during growth period, especially in male rats.

本研究探讨了妊娠期2,3,7,8-TeCDD （TeCDD）对大鼠子代运动发育和学习过程的影响。妊娠大鼠在妊娠第9 ~ 19天口服TeCDD或玉米油。暴露组和对照组的后代在出生后都可以自由地获得母乳，断奶后可以获得食物和水。进行了以下实验并得到了结果：TeCDD对胎儿大脑的影响：在妊娠第19天，将6例TeCDD组胎儿和5例对照组胎儿从子宫中取出。从胎儿身上采集大脑，并将其分为三部分：大脑、小脑和下丘脑。TeCDD组每全脑下丘脑比例显著高于对照组。TeCDD对后代的影响：在出生后第4天至第14天，测量在斜坡上转身的时间，测试运动发育。在7 ~ 11天内，TeCDD组的潜伏时间显著长于对照组。从出生后第31天至44天，每天用音调和电击调节后，检查穿梭箱中回避行为的表现。与对照组相比，TeCDD组雄性大鼠在这些天的逃逸率和逃逸潜伏期的改善有所延迟。此外，暴露于TeCDD的雄性大鼠自发性活动也较低。在行为检查后的解剖调查中也发现了TeCDD组每脑下丘脑的增加率。这些结果表明，怀孕期间暴露于TeCDD会影响后代在生长期的神经发育，尤其是雄性大鼠。