TY - JOUR
T1 - Toxic effects of triclocarban on larval zebrafish
T2 - A focus on visual dysfunction
AU - Chen, Xiao Fan
AU - Chen, Zhi Feng
AU - Lin, Zhi Cheng
AU - Liao, Xiao Liang
AU - Zou, Ting
AU - Qi, Zenghua
AU - Cai, Zongwei
N1 - The present study was funded by the National Natural Science Foundation of China (42177254), the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01Z032), National Key Research and Development Project (2019YFC1804604), Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety (2019B030301008), Science and Technology Planning Project of Guangdong Province (2020B1212030008). We thank China Zebrafish Resource Center (CZRC) for providing the zebrafish.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/12
Y1 - 2021/12
N2 - Triclocarban (TCC) is considered an endocrine disruptor and shows antagonist activity on thyroid receptors. In view of the report that thyroid hormone signaling mediates retinal cone photoreceptor specification, we hypothesize that TCC could impair visual function, which is vital to wildlife. In order to verify our hypothesis, we assessed alteration in the retinal structure (retinal layer thickness and cell density), visually-mediated behavior, cone and rod opsin gene expression, and photoreceptor immunostaining in zebrafish larvae exposed to TCC at environmentally realistic concentrations (0.16 ± 0.005 µg/L, L-group) and one-fifth of the median lethal concentrations (25.4 ± 1.02 µg/L, H-group). Significant decrease in eye size, ganglion cell density, optokinetic response, and phototactic response can be observed in the L-group, while the thickness of outer nuclear layer, where the cell bodies of cone and rod cells are located, was significantly reduced with the down-regulation of critical opsin gene (opn1sw2, opn1mw1, opn1mw3, opn1lw1, opn1lw2, and rho) expression and rhodopsin immunofluorescence in the H-group. It should be noted that TCC could affect the sensitivity of zebrafish larvae to red and green light according to the results of behavioral and opsin gene expression analysis. These findings provide the first evidence to support our hypothesis that the visual system, a novel toxicological target, is affected by TCC. Consequently, we urgently call for a more in-depth exploration of TCC-induced ocular toxicity to aquatic organisms and even to humans.
AB - Triclocarban (TCC) is considered an endocrine disruptor and shows antagonist activity on thyroid receptors. In view of the report that thyroid hormone signaling mediates retinal cone photoreceptor specification, we hypothesize that TCC could impair visual function, which is vital to wildlife. In order to verify our hypothesis, we assessed alteration in the retinal structure (retinal layer thickness and cell density), visually-mediated behavior, cone and rod opsin gene expression, and photoreceptor immunostaining in zebrafish larvae exposed to TCC at environmentally realistic concentrations (0.16 ± 0.005 µg/L, L-group) and one-fifth of the median lethal concentrations (25.4 ± 1.02 µg/L, H-group). Significant decrease in eye size, ganglion cell density, optokinetic response, and phototactic response can be observed in the L-group, while the thickness of outer nuclear layer, where the cell bodies of cone and rod cells are located, was significantly reduced with the down-regulation of critical opsin gene (opn1sw2, opn1mw1, opn1mw3, opn1lw1, opn1lw2, and rho) expression and rhodopsin immunofluorescence in the H-group. It should be noted that TCC could affect the sensitivity of zebrafish larvae to red and green light according to the results of behavioral and opsin gene expression analysis. These findings provide the first evidence to support our hypothesis that the visual system, a novel toxicological target, is affected by TCC. Consequently, we urgently call for a more in-depth exploration of TCC-induced ocular toxicity to aquatic organisms and even to humans.
KW - ocular toxicity
KW - optokinetic response
KW - retinal layer
KW - Triclocarban
KW - zebrafish
UR - http://www.scopus.com/inward/record.url?scp=85118235012&partnerID=8YFLogxK
U2 - 10.1016/j.aquatox.2021.106013
DO - 10.1016/j.aquatox.2021.106013
M3 - Journal article
C2 - 34731642
AN - SCOPUS:85118235012
SN - 0166-445X
VL - 241
JO - Aquatic Toxicology
JF - Aquatic Toxicology
M1 - 106013
ER -