孕期镉暴露对小鼠胎盘氨基酸转运系统的影响及其作用机制的研究  

Effects of maternal cadmium exposure on the placental amino acid transport system and the underlying mechanisms

作　　者：孟然[1] 戚红[1] 毛学群[1] 许鹏[2] 

机构地区：[1]北京市海淀区妇幼保健院,100080 [2]山西大学生命科学学院,太原030006

出　　处：《中国优生与遗传杂志》2017年第11期13-17,共5页Chinese Journal of Birth Health & Heredity

摘　　要：目的探究孕期镉暴露对小鼠胎盘氨基酸转运系统的影响及其作用机制。方法选择45只体重相近的孕鼠,于妊娠第7.5天(Embryonic 7.5,E7.5)时,随机(完全随机化法)分为3组,分别喂食0,20mg/L和40mg/L的氯化镉溶液。分别于E13.5天、E16.5天和E19.5天收集各组小鼠的胎盘组织标本和血浆样本,每一妊娠阶段5只动物。通过实时定量PCR技术检测各组小鼠胎盘中L型转运载体-1(L-type amino acid transporter 1,LAT1)、L型转运载体-2(L-type amino acid transporter 2,LAT2)、L型转运载体-3(L-type amino acid transporter 3,LAT3)、L型转运载体-4(L-type amino acid transporter 4,LAT4)、A型转运载体-1(sodium-coupled neutral amino acid transporter 1,SNAT1)和A型转运载体-2(sodium-coupled neutral amino acid transporter 2,SNAT2)的m RNA表达情况,并对其中差异表达的分子进一步通过蛋白印迹法鉴定其蛋白质水平的变化情况。此外,采用可见光比色法检测各组小鼠血浆中氨基酸的含量。结果 (1)3组孕鼠胎盘中LAT1、LAT2、LAT3、LAT4、SNAT1和SNAT2的m RNA表达水平的比较:3组孕鼠胎盘中的LAT1分子,E19.5天时在40mg/L镉处理组的小鼠胎盘中的m RNA表达水平与正常对照组相比显著性降低,而在E16.5天时无显著性变化。其他5种氨基酸转运载体在不同浓度镉处理组的小鼠胎盘中的m RNA表达水平与正常对照组相比,在E16.5天和E19.5天时均没有显著性变化。(2)3组孕鼠胎盘中LAT1蛋白质表达水平的比较:E16.5天时,与正常对照组相比,不同浓度镉处理组小鼠胎盘中的LAT1蛋白表达水平出现降低,并且40mg/L镉处理组的小鼠胎盘中的LAT1蛋白质表达水平出现显著性变化。E19.5天时,与正常对照组相比,20mg/L和40mg/L镉处理组小鼠胎盘的LAT1蛋白表达水平均明显降低。(3)3组孕鼠血浆中氨基酸含量的比较:E19.5天时,不同浓度镉处理组的小鼠血浆中氨基酸含量与正常对照组相比均出现降低,并且40mg/L镉处理组Objective：To investigate the effects of maternal cadmium exposure on the placental amino acid transport system and the underlying mechanisms. Methods：Forty-five pregnant mice were randomly divided into three groups：control,experimental 1（20 mg/L of Cd）and experimental 2（40 mg/L of Cd）.Drinking water with or without Cd was supplied from Embryonic Day（E）7.5 to the end of the study.The dams of these three groups were sacrificed on embryonic days E13.5,E16.5 and E19.5 separately. All placentas and plasma samples were collected for analyses. Quantitative real-time PCR and western blotting experiments were performed to screen the differential expression of L-type amino acid transporters 1（LAT1）,2（LAT2）,3（LAT3）and 4（LAT4）as well as sodium-coupled neutral amino acid transporters 1（SNAT1）and 2（SNAT2）. The amino acid levels in the plasma were also quantified. Results：（1）The placental m RNA levels：placental LAT1 expression was lower in the 40 mg/L Cd-exposed placentas than that in the controls.（2）The placental protein levels：placental LAT1 protein levels in the 40 mg/L treatment groups were significantly decreased at E16.5 and E19.5. The placental LAT1 protein levels in the 20 mg/L group was decreased at E19.5.（3）The amino acid levels in the plasma：the amino acid levels in the plasma of 40 mg/L groups wasdecreased at E19.5. Conclusions：Changes in the expression levels of placental LAT1 and amino acid levels of the plasma may be involved in the etiology of fetal growth restriction induced by maternal Cd exposure. The decrease of amino acid levels in the plasma of the Cd-exposed group may participate in the downregulation of the placental LAT1.

关 键 词：胎儿生长受限 胎盘 氨基酸转运 镉 

分 类 号：R114[医药卫生—卫生毒理学]