Mechanisms of cadmium-caused eye hypoplasia and hypopigmentation in zebrafish embryos.
Cadmium-caused head and eye hypoplasia and hypopigmentation has been recognized for a long time, but knowledge of the underlying mechanisms is limited. In this study, we found that high mortality occurred in exposed embryos after 24 hpf, when cadmium (Cd) dosage was above 17.8 μM. Using high-throughput in situ hybridization screening, we found that genes labelling the neural crest and its derivative pigment cells exhibited obviously reduced expression in Cd-exposed embryos from 24 hpf, 2 days earlier than head and eye hypoplasia and hypopigmentation occurred. Moreover, based on expression of crestin, a neural crest marker, we found that embryos before the gastrula stage were more sensitive to cadmium toxicity and that damage caused by Cd on embryogenesis was dosage dependent. In addition, by phenotype observation and detection of neural crest and pigment cell markers, we found that BIO and retinoic acid (RA) could neutralize the toxic effects of Cd on zebrafish embryogenesis. In this study, we first determined that Cd blocked the formation of the neural crest and inhibited specification of pigment cells, which might contribute to the molecular mechanisms underlying the phenotype defects of head and eye hypoplasia and hypopigmentation in Cd-exposed embryos. Moreover, we found that compounds BIO or RA could neutralize the toxic effects of Cd.
College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: zting@webmail.hzau.edu.cn.
Ting
T
Zhang
College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: 290356082@qq.com.
Xin-Ying
XY
Zhou
College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: xufama@mail.hzau.edu.cn.
Xu-Fa
XF
Ma
College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: ichliu@mail.hzau.edu.cn.
Jing-Xia
JX
Liu
D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D047108:Embryonic Development / Q000187:drug effects; D017496:Hypopigmentation / Q000139:chemically induced; D009432:Neural Crest / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000196:embryology*
D014874:Water Pollutants, Chemical; D002104:Cadmium
BIO; Cadmium; High-throughput in situ hybridization screening; Neural crest; Pigment cells; RA; Zebrafish