Chronic effects of triclosan on embryonic development of Chinese toad, Bufo gargarizans

Abstract

Triclosan (TCS) is commonly used worldwide in a range of personal care and sanitizing products. The aim of this study was to evaluate potential effects of TCS exposure on embryonic development of Bufo gargarizans, an endemic frog species in China. Standard Gosner stage 3 B. gargarizans embryos were exposed to 10 ~ 150 μg/L TCS during embryogenesis. Survival, total length, weight, developmental stage, duration of different embryo stages, malformation, and type II and III deiodinase (D2 and D3) expression were measured. Inhibitory effects on embryo developmental stage, total length and weight were found at 30 ~ 150 μg/L TCS. Moreover, the duration of embryonic development was increased at gastrula, neural, circulation, and operculum development stage in TCS-treated groups. In addition, TCS exposure induced morphological malformations in B. gargarizans embryos, which are characterized by hyperplasia, abdominal edema, and axial flexures. Furthermore, our results showed that the expression of D2 in embryos was probably down-regulated at 60 and 150 μg/L TCS, but its spatial expression patterns was not affected by TCS. In summary, our study suggested that TCS exposure not only resulted in delayed growth and development but also caused teratogenic effects in B. gargarizans embryos, and the developmental effects of TCS at high concentrations may be associated with disruption of THs homeostasis. Although further studies are necessary, the present findings could provide a basis for understanding on harmful effects and the potential mechanisms of TCS in amphibian embryos.

P38/TRHr-Dependent Regulation of TPO in Thyroid Cells Contributes to the Hypothyroidism of Triclosan-Treated Rats

“…Similar results were also found in other studies [22]. However, the study reported that D2 expression was downregulated in gargarizans embryos that were exposed to 60 and 150 µg/L triclosan [23]. We analyze that differences of research models may explain the diverse effects of triclosan on deiodinases.…”

Inhibition of Metamorphosis, Thyroid Gland, and Skeletal Ossification Induced by Hexavalent Chromium in Bufo gargarizans Larvae

“…Chinese toad (Bufo gargarizans) is one of the most common amphibian species and is widely distributed in eastern Asia. In previous studies, B. gargarizans has been used as a test organism in the assessment of the potential toxic effects of aquatic pollutants, including copper (Xia et al 2012;Wang et al 2016), Cr (VI) (Li et al 2018;Yao et al 2019;Yang et al 2020), triclosan (Chai et al 2016b(Chai et al , 2017a, lead (Chai et al 2017b;Yang et al 2019), cadmium (Wu et al 2017a(Wu et al , 2017b, fluoride (Bo et al 2018;Wu et al 2018;Wang et al 2019), nitrate (Wang et al 2015;Xie et al 2019), and spirotetramat (Yin et al 2014). Although the adverse effects of Cr (VI) on B. gargarizans have been explored in previous studies, they mainly focused on the embryonic stage (Li et al 2018), gut microbiota (Yao et al 2019), or liver (Yang et al 2020).…”