Exposure to butachlor causes thyroid endocrine disruption and promotion of metamorphosis in Xenopus laevis. (June 2016)

• Record Type: Journal Article
• Authors: Li, Shuying; Li, Meng; Wang, Qiangwei; Gui, Wenjun; Zhu, Guonian
• Is Part Of: Chemosphere. Volume 152(2016)
• Page Start: 158
• Page End: 165
• Publication Date: 2016-06
• Subjects: Butachlor -- Xenopus laevis -- Malformation -- Thyroid endocrine disruption -- Developmental toxicity; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2016.02.098
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Butachlor is extensively applied in rice paddy ecosystem in china, and has been widespread contaminant in the aquatic environment. Here, Xenopus laevis was used for the evaluation of teratogenesis developmental toxicity, and disruption of thyroid system when exposure to different concentrations of butachlor by window phase exposure. Acute toxicity investigation shown that 96 h-LC50 value of butachlor was 1.424 mg L −1 and 0.962 mg L −1 for tadpoles (starting from stages 46/47) and embryos (starting from stages 8/9), respectively. Exposure to butachlor caused malformation, including abnormal eye, pericardial edema, enlarged proctodaeum and bent tail. Window phase exposure test indicated that butachlor significantly promote the contents of whole-body thyroid hormones (THs, T3 and T4 ) at higher levels, indicating thyroid endocrine disruption. At 7 days, exposure to butachlor up-regulated the mRNA expression of genes involved in THs synthesis and metabolism ( tsh α, tg, tpo and dio 1) and THs receptors ( tr α and tr β). At 14 days, up-regulation of the mRNA expression of genes related to THs synthesis and metabolism ( tsh α, tsh β, tg, tpo, dio1, dio2 and ttr ) and THs receptors ( tr β) were also observed after the exposure to butachlor. At 21 days, butachlor up-regulated the mRNA expression of tsh α, tg, tpo genes and down-regulated the mRNA expression of tsh β, tg, dio1, ttr and tr α genes. These results showed that butachlor could change the mRNA expression of genes involved in the HPT axis and increase whole-body thyroid hormones levels of X . laevis tadpoles in a dose- and time-dependent manner, causing thyroid endocrine disruption and developmental toxicity. Graphical abstract: Highlights: Monitoring of butachlor in a typical rice paddy field. Butachlor showed adverse metamorphosis effects in tadpole. Butachlor significantly promote the contents of whole-body thyroid hormones (THs, T3 and T4) at higher levels. Butachlor increased THs levels and altered the expression of genes involved in the HPT axis of Xenopus laevis tadpole.