Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, PR China.
Benxi Institute for Drug Control, No.31 Shengli Road, Mingshan District, Benxi 117000, PR China.
Sci Total Environ. 2019 Jun 1;667:586-593. doi: 10.1016/j.scitotenv.2019.02.419. Epub 2019 Feb 28.
The endocrine disrupting effect of pesticides is considered to be an important factor in the decline of reptile populations. The large-scale application of neonicotinoids in the environment poses a potential threat to small farmland lizards Eremias argus. In this study, we evaluated the disruption effects of thiamethoxam and its metabolite clothianidin on the endocrine disruption of Eremias argus during 28 d exposure. Thiamethoxam and clothianidin could accumulate in the testis and ovary. Adequate blood exchange was the main cause of thiamethoxam and clothianidin accumulation in the gonads. The production of clothianidin aggravated the effect of endocrine disruption to lizards. Thiamethoxam/clothianidin exhibited two distinct ways of interfering with the endocrine disruption of the male and female lizards. Thiamethoxam/clothianidin significantly up-regulated the expression of cyp17 and cyp19 genes in the testis, which ultimately led to a significant decrease in testosterone levels and a significant increase in the 17-estradiol concentrations in plasma. The expression of the estrogen receptor gene in the liver was also significantly increased in male lizards. The significant declines in testosterone and prostaglandin D2 levels in the plasma indicated that thiamethoxam and clothianidin could cause androgen deficiency in male lizards. Meanwhile, in female lizards, thiamethoxam/clothianidin increased the expression of hsd17β gene in the ovary, causing an increase in testosterone levels in the plasma and an up-regulation of androgen receptor expression in the liver. The effects of thiamethoxam and clothianidin on male lizards were more pronounced. This study verified the possible endocrine disrupting effects of neonicotinoids and provided a new perspective for the study of global recession of reptiles.
杀虫剂的内分泌干扰作用被认为是爬行动物种群减少的一个重要因素。新烟碱类杀虫剂在环境中的大规模应用对小型农田蜥蜴 Eremias argus 构成了潜在威胁。在这项研究中，我们评估了噻虫嗪及其代谢物噻虫胺对 28 天暴露期间 Eremias argus 内分泌干扰的破坏作用。噻虫嗪和噻虫胺可以在睾丸和卵巢中积累。充分的血液交换是噻虫嗪和噻虫胺在性腺中积累的主要原因。噻虫胺的产生加剧了对蜥蜴内分泌干扰的影响。噻虫嗪/噻虫胺对雄性和雌性蜥蜴的内分泌干扰表现出两种截然不同的方式。噻虫嗪/噻虫胺显著上调了睾丸中 cyp17 和 cyp19 基因的表达，最终导致睾酮水平显著降低，血浆中 17-雌二醇浓度显著升高。雄性蜥蜴肝脏中雌激素受体基因的表达也显著增加。血浆中睾酮和前列腺素 D2 水平的显著下降表明，噻虫嗪和噻虫胺可导致雄性蜥蜴雄激素缺乏。同时，在雌性蜥蜴中，噻虫嗪/噻虫胺增加了卵巢中 hsd17β 基因的表达，导致血浆中睾酮水平升高，肝脏中雄激素受体表达上调。噻虫嗪和噻虫胺对雄性蜥蜴的影响更为明显。本研究验证了新烟碱类杀虫剂可能具有内分泌干扰作用，并为研究爬行动物全球衰退提供了新视角。
