Jin Yuanxiang, Chen Rujia, Sun Liwei, Wang Wanyuan, Zhou Lin, Liu Weiping, Fu Zhengwei
College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
Chemosphere. 2009 Mar;74(9):1238-44. doi: 10.1016/j.chemosphere.2008.11.015. Epub 2008 Dec 17.
Enantioselectivity in the separation, toxicology, biodegradation and estrogenic activity of chiral pesticides has become a groundbreaking topic recently. In this study, real-time, quantitative polymerase chain reaction was adapted to investigate the induction of estrogen-responsive gene expression in embryo-larval zebrafish after 7 d of exposure to permethrin (PM) enantiomers. The PM enantiomers were completely separated by a chiral HPLC column. The in vivo study found that a 7 d exposure to 250 ng L(-1) PM racemate and its enantiomers was sufficient to stimulate vtg1, esralpha and cyp19b expression, while 1000 ng L(-1) exposure significantly induced gene expression in a pattern similar to that of the control (50 ng L(-1) E2), except for vtg2. Significant differences were detected between the enantiomers in the induction of estrogen-responsive gene expression. At the exposure level of 1000 ng L(-1), the vtg1, esralpha and cyp19b responses to the (-)-trans enantiomer were about 3.2-, 1.8- and 1.5-fold higher, respectively, than those in the group treated with (+)-trans enantiomer (p < 0.05). In the two cis-enantiomer treatment groups, (+)-cis increased the mRNA level of the cyp19b gene about 1.5-fold higher than the (-)-cis-enantiomer did. Of the four enantiomers, the (-)-trans enantiomer showed the greatest estrogenic activity. The results strongly indicate the occurrence of significant enantioselectivity in estrogenic activity of PM enantiomers exposed to embryo-larval zebrafish. These findings add to a growing body of evidence concerning enantioselectivity in the toxicity, endocrine-disrupting activity, and environmental biodegradation of chiral pesticides.
手性农药在分离、毒理学、生物降解及雌激素活性方面的对映体选择性已成为近年来一个具有开创性的课题。本研究采用实时定量聚合酶链反应，以研究斑马鱼胚胎-幼体暴露于氯菊酯（PM）对映体7天后雌激素反应性基因表达的诱导情况。PM对映体通过手性高效液相色谱柱完全分离。体内研究发现，暴露于250 ng L(-1)的PM外消旋体及其对映体7天足以刺激vtg1、esralpha和cyp19b的表达，而暴露于1000 ng L(-1)时，除vtg2外，基因表达显著诱导，其模式与对照组（50 ng L(-1) E2）相似。在雌激素反应性基因表达的诱导方面，对映体之间检测到显著差异。在1000 ng L(-1)的暴露水平下，(-)-反式对映体对vtg1、esralpha和cyp19b的反应分别比对(+)-反式对映体处理组高约3.2倍、1.8倍和1.5倍（p < 0.05）。在两个顺式对映体处理组中，(+)-顺式使cyp19b基因的mRNA水平比(-)-顺式对映体增加约1.5倍。在四种对映体中，(-)-反式对映体表现出最大的雌激素活性。结果有力地表明，暴露于斑马鱼胚胎-幼体的PM对映体在雌激素活性方面存在显著的对映体选择性。这些发现为有关手性农药在毒性、内分泌干扰活性和环境生物降解方面的对映体选择性的证据不断增加做出了贡献。
