影响胚胎早期发育环境因素的研究进展

妊娠期生理状态的改变，使母体对治疗药物和各种环境有害物质的吸收、分布和排泄发生了较大的改变。在发育初期，胚胎对治疗药物和环境因素的影响极为敏感，此时各种有害因素都可导致胚胎的损伤，甚至丢失。许多药物和环境因素是引起早期胚胎死亡或胎儿畸形的主要因素。环境类激素可直接作用于中枢神经内分泌调节系统，引起生殖激素分泌紊乱，出现生殖率下降和胚胎发育异常。重金属铅、镉、汞、砷可导致早期胚胎的丢失，或使胎儿出现畸形。对于药物和环境因素对胚胎发育的毒性评估，妊娠动物服用的剂量对妊娠结果仍然是最基本的方法，而用BBDR模型来反映药物在低剂量情况下的作用以及在种间变化是近年来常用的模型。另一方面，细胞和分子的水平上观察环境毒物造成畸胎发生的机理也是活跃的研究领域。

The Studying Development of Effect of Enviromental Factors on Early Embryo

During pregnancy, the metabolism process in the organs and tissues of mother body undergoes a major change and become more sensitive to environmental factors. Many hazard factors can exert harmful effects toward the fetal and cause damage outcome, especially in the embryo developing stage. Environmental estrogen like substances can impact on the central nerve and endocrine system directly, causing abnormal secretion of reproduction hormones, leading to low reproduction rate and abnormal developing of embryos. Heavy metals such as Pb, Cd, Hg and As can cause the lossing fetal or malformation of embryos. For evaluation of toxicity of drug and environmental factor to developing embryos, the dosage take by pregnant animal and the responding outcome still is the most essential method. BBDR model which can reflect the effect of drugs in low level and analyses the effect among species of different animals is among the most used protocols. However, observation of embryo malformation caused by environmental reagents in cell and molecular levels, which may explain the mechanisms, is another active field.