Chang Jing, Li Wei, Guo Baoyuan, Xu Peng, Wang Yinghuan, Li Jianzhong, Wang Huili
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China; University of Chinese Academy of Sciences, Yuquan RD 19 A, Beijing, 100049, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China.
Chemosphere. 2017 Apr;172:210-216. doi: 10.1016/j.chemosphere.2017.01.002. Epub 2017 Jan 4.
Flufenoxuron is a widely used pesticide to inhibit the synthesis of chitin during insect development and its effect on the growth of lizards has been little addressed. The hypothalamus-pituitary-thyroid (HPT) axis plays an important role on the development of lizards. In this study, the lizards at different development stages (proliferation and resting stages) were exposed to flufenoxuron for 21 days. The plasma thyroid hormone levels, thyroid gland histopathology and expression profiles of thyroid hormone receptors (trα, trβ), deiodinases (dio1, dio2), and transthyretin (ttr) genes were measured to evaluated the toxic effect of flufenoxuron on the HPT axis at different stages. The flufenoxuron exposure showed more seriously effect on the triiodothyronine (T3) level at resting phase than that at proliferation stage. The follicle epithelium cell height in the thyroid was only significantly increased when the exposed male lizards were at proliferation stage. The alteration of HPT axis-related genes expression was gender and tissue dependent after flufenoxuron treatment. The lizards exposed to flufenoxuron showed that the trα, trβ, dio1, dio2, and ttr genes in the female liver were more sensitive at the proliferation stage than that at the resting stage. In the male brain, the expressions of trα, trβ, dio1, and dio2 gene were significant decreased at proliferation stage while significant increased at resting stage after flufenoxuron exposure. Therefore, the thyroid endocrine system of lizards could be affected by the flufenoxuron exposure and the different development stage should also be considered when study the toxic effect of contaminants on the lizards.
氟虫脲是一种广泛使用的杀虫剂，可在昆虫发育过程中抑制几丁质的合成，而其对蜥蜴生长的影响鲜有研究。下丘脑 - 垂体 - 甲状腺（HPT）轴在蜥蜴的发育中起重要作用。在本研究中，将处于不同发育阶段（增殖期和静止期）的蜥蜴暴露于氟虫脲中21天。检测血浆甲状腺激素水平、甲状腺组织病理学以及甲状腺激素受体（trα、trβ）、脱碘酶（dio1、dio2）和转甲状腺素蛋白（ttr）基因的表达谱，以评估氟虫脲在不同阶段对HPT轴的毒性作用。氟虫脲暴露对静止期三碘甲状腺原氨酸（T3）水平的影响比对增殖期更严重。仅在暴露的雄性蜥蜴处于增殖期时，甲状腺中的滤泡上皮细胞高度才显著增加。氟虫脲处理后，HPT轴相关基因表达的改变具有性别和组织依赖性。暴露于氟虫脲的蜥蜴显示，雌性肝脏中的trα、trβ、dio1、dio2和ttr基因在增殖期比静止期更敏感。在雄性大脑中，氟虫脲暴露后，trα、trβ、dio1和dio2基因在增殖期的表达显著降低，而在静止期显著增加。因此，蜥蜴的甲状腺内分泌系统可能会受到氟虫脲暴露的影响，在研究污染物对蜥蜴的毒性作用时也应考虑不同的发育阶段。
