Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China; University of Chinese Academy of Sciences, Yuquan RD 19 a, Beijing 100049, China.
Binzhou People's Hospital ICU, China.
Environ Pollut. 2018 Jan;232:300-309. doi: 10.1016/j.envpol.2017.09.072. Epub 2017 Sep 29.
The disturbance of the thyroid system and elimination of chiral pyrethroid pesticides with respect to enantioselectivity in reptiles have so far received limited attention by research. In this study, bioaccumulation, thyroid gland lesions, thyroid hormone levels, and hypothalamus-pituitary-thyroid axis-related gene expression in male Eremias argus were investigated after three weeks oral administration of lambda-cyhalothrin (LCT) enantiomers. In the lizard liver, the concentration of LCT was negatively correlated with the metabolite-3-phenoxybenzoic acid (PBA) level during 21 days of exposure. (+)-LCT exposure induced a higher thyroid follicular epithelium height than (-)-LCT exposure. The thyroxine levels were increased in both treated groups while only (+)-LCT exposure induced a significant change in the triiodothyronine (T3) level. In addition, the expressions of hypothalamus-pituitary-thyroid axis-related genes including thyroid hormone receptors (trs), deiodinases (dios), uridinediphosphate glucuronosyltransferase (udp), and sulfotransferase (sult) were up-regulated after exposure to the two enantiomers. (+)-LCT treatment resulted in higher expression of trs and (-)-LCT exposure led to greater stimulation of dios in the liver, which indicated PBA-induced antagonism on thyroid hormone receptors and LCT-induced disruption of thyroxine (T4) deiodination. The results suggest the (-)-LCT exposure causes higher residual level in lizard liver while induces less disruption on lizard thyroid activity than (+)-LCT.
迄今为止，有关手性拟除虫菊酯类杀虫剂在爬行动物体内的甲状腺系统干扰和对映体选择性消除的研究还很有限。本研究采用雄性荒漠麻蜥（Eremias argus）为实验动物，经口灌胃染毒 3 周后，研究了λ-氯氰菊酯（LCT）对映体暴露对荒漠麻蜥肝脏的生物累积、甲状腺损伤、甲状腺激素水平及下丘脑-垂体-甲状腺轴相关基因表达的影响。在 21 天的暴露期间，荒漠麻蜥肝脏中 LCT 的浓度与代谢产物 3-苯氧基苯甲酸（PBA）水平呈负相关。（+）-LCT 暴露引起的甲状腺滤泡上皮细胞高度增加高于（-）-LCT 暴露。与对照组相比，两个处理组的甲状腺素（T4）水平均升高，而仅（+）-LCT 暴露引起三碘甲状腺原氨酸（T3）水平的显著变化。此外，暴露于两种对映体后，下丘脑-垂体-甲状腺轴相关基因（包括甲状腺激素受体（trs）、脱碘酶（dios）、尿苷二磷酸葡萄糖醛酸转移酶（udp）和磺基转移酶（sult））的表达均上调。（+）-LCT 处理导致 trs 表达上调，（-）-LCT 暴露导致肝脏中 dios 表达上调，表明 PBA 诱导了甲状腺激素受体的拮抗作用，而 LCT 则破坏了 T4 的脱碘作用。结果表明，（-）-LCT 暴露在蜥蜴肝脏中残留水平较高，而对蜥蜴甲状腺功能的破坏程度低于（+）-LCT。
