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目的 探讨动物妊娠早期接触2 ,3 ,7,8 四氯苯二(TCDD)后造成胚胎丢失的原因以及对小鼠成活率的影响。方法 90只妊娠NHI小鼠分9组,在妊娠的第1天,第2天和第3天分别观察胚胎转移率、检测血清雌二醇和孕酮含量;2 40只妊娠NIH小鼠分2 4组,于妊娠第9天和第18天测定子宫重量,观察胚胎成活情况。结果 与正常对照组胚胎数比较,TCDD未影响胚胎转移率,但造成着床前胚胎丢失(14±4 2 0 ,4 63±6 0 9,P <0 0 1) ;不同时期染毒均可降低胚胎和胎儿成活率(P <0 0 0 1) ;血清雌二醇含量升高(P <0 0 0 1)、孕酮水平下降(P <0 0 1)。结论 TCDD对胚胎和母体均具有毒性,血清类固醇激素的改变可影响子宫功能,造成第9天胚胎成活率下降;同时TCDD具有持续毒性的特点,使出生前第18天胚胎成活数低于第9天胚胎成活数。
Objective To investigate the causes of embryo loss after exposure to 2,3,7,8-tetrachlorodiphenolide (TCDD) in early pregnancy and the effect on the survival rate of mice. Methods 90 pregnant NHI mice were randomly divided into 9 groups. The embryo transfer rates were observed on the 1st, 2nd and 3rd day of gestation. Serum estradiol and progesterone levels were measured. The uterus weights were measured on the 9th and 18th days of pregnancy, and the survival of the embryos was observed. Results Compared with the normal control group, TCDD did not affect the rate of embryo transfer but resulted in loss of preimplantation embryos (14 ± 4 2 0, 4 63 ± 6 0 9, P 0 01) (P <0.01). Serum estradiol level increased (P <0.01) and progesterone level decreased (P <0.01). Conclusions TCDD is toxic to embryos and maternal body. Changes of serum steroid hormones may affect uterine function, resulting in a decrease of embryonic survival rate on the 9th day. At the same time, TCDD is characterized by persistent toxicity. The embryonic viability at 18 days before birth is lower than that of 9th Days of embryos to survive.