Shi Xiongjie, Du Yongbing, Lam Paul K S, Wu Rudolf S S, Zhou Bingsheng
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
Toxicol Appl Pharmacol. 2008 Jul 1;230(1):23-32. doi: 10.1016/j.taap.2008.01.043. Epub 2008 Feb 20.
Perfluorooctanesulfonate (PFOS) is a persistent organic pollutant, the potential toxicity of which is causing great concern. In the present study, we employed zebrafish embryos to investigate the developmental toxicity of this compound. Four-hour post-fertilization (hpf) zebrafish embryos were exposed to 0.1, 0.5, 1, 3 and 5 mg/L PFOS. Hatching was delayed and hatching rates as well as larval survivorship were significantly reduced after the embryos were exposed to 1, 3 and 5 mg/L PFOS until 132 hpf. The fry displayed gross developmental malformations, including epiboly deformities, hypopigmentation, yolk sac edema, tail and heart malformations and spinal curvature upon exposure to PFOS concentrations of 1 mg/L or greater. Growth (body length) was significantly reduced in the 3 and 5 mg/L PFOS-treated groups. To test whether developmental malformation was mediated via apoptosis, flow cytometry analysis of DNA content, acridine orange staining and TUNEL assay was used. These techniques indicated that more apoptotic cells were present in the PFOS-treated embryos than in the control embryos. Certain genes related to cell apoptosis, p53 and Bax, were both significantly up-regulated upon exposure to all the concentrations tested. In addition, we investigated the effects of PFOS on marker genes related to early thyroid development (hhex and pax8) and genes regulating the balance of androgens and estrogens (cyp19a and cyp19b). For thyroid development, the expression of hhex was significantly up-regulated at all concentrations tested, whereas pax8 expression was significantly up-regulated only upon exposure to lower concentrations of PFOS (0.1, 0.5, 1 mg/L). The expression of cyp19a and of cyp19b was significantly down-regulated at all exposure concentrations. The overall results indicated that zebrafish embryos constitute a reliable model for testing the developmental toxicity of PFOS, and the gene expression patterns in the embryos were able to reveal some potential mechanisms of developmental toxicity.
全氟辛烷磺酸（PFOS）是一种持久性有机污染物，其潜在毒性引起了人们的高度关注。在本研究中，我们利用斑马鱼胚胎来研究该化合物的发育毒性。将受精后4小时（hpf）的斑马鱼胚胎暴露于0.1、0.5、1、3和5mg/L的PFOS中。胚胎暴露于1、3和5mg/L的PFOS直至132 hpf后，孵化延迟，孵化率和幼体存活率显著降低。鱼苗出现明显的发育畸形，包括外包畸形、色素沉着不足、卵黄囊水肿、尾巴和心脏畸形以及脊柱弯曲，当暴露于1mg/L或更高浓度的PFOS时。在3和5mg/L PFOS处理组中，生长（体长）显著降低。为了测试发育畸形是否通过凋亡介导，使用了DNA含量的流式细胞术分析、吖啶橙染色和TUNEL测定。这些技术表明，PFOS处理的胚胎中存在比对照胚胎更多的凋亡细胞。在暴露于所有测试浓度下，与细胞凋亡相关的某些基因p53和Bax均显著上调。此外，我们研究了PFOS对与早期甲状腺发育相关的标记基因（hhex和pax8）以及调节雄激素和雌激素平衡的基因（cyp19a和cyp19b）的影响。对于甲状腺发育，在所有测试浓度下hhex的表达均显著上调，而仅在暴露于较低浓度的PFOS（0.1、0.5、1mg/L）时pax8表达显著上调。在所有暴露浓度下，cyp19a和cyp19b的表达均显著下调。总体结果表明，斑马鱼胚胎构成了测试PFOS发育毒性的可靠模型，并且胚胎中的基因表达模式能够揭示发育毒性的一些潜在机制。
