Tao Yixi, Du Chunying, Duan Bicheng, Wang Wenbo, Guo Hui, Feng Jingyun, Xu Hao, Li Yun
Fisheries and Aquaculture Biotechnology Laboratory, College of Fisheries, Southwest University, Chongqing 400715, China.
Fisheries and Aquaculture Biotechnology Laboratory, College of Fisheries, Southwest University, Chongqing 400715, China; Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University, Chongqing 400715, China.
Comp Biochem Physiol C Toxicol Pharmacol. 2023 Jun;268:109602. doi: 10.1016/j.cbpc.2023.109602. Epub 2023 Mar 9.
Eugenol is a natural phenolic essential oil extracted from cloves, that has analgesic and anesthetic effects and is widely used in fishery anesthesia. However, the potential safety risks of aquaculture production associated with the massive use of eugenol and its developmental toxicity during early life stages of fish have been overlooked. In this study, zebrafish (Danio rerio) embryos at 24 hours post-fertilization (hpf) were exposed to eugenol at concentrations of 0, 10, 15, 20, 25, or 30 mg/L for 96 h. Eugenol exposure delayed the hatching of zebrafish embryos, and reduced the body length and the inflation rate of the swim bladder. The accumulated number of dead zebrafish larvae in the eugenol-exposed groups was higher than that of the control group, and it was dose-dependent. Real-time quantitative polymerase chain reaction (qPCR) analysis showed that the Wnt/β-catenin signaling pathway that regulates the development of the swim bladder during the hatching and mouth-opening stages was inhibited after eugenol exposure. Specifically, the expression of wif1, a Wnt signaling pathway inhibitor, was significantly up-regulated, whereas the expression of fzd3b, fzd6, ctnnb1, and lef1 involved in the Wnt/β-catenin pathway was significantly down-regulated. These results suggest that the failure of zebrafish larvae to inflate their swim bladders as a result of eugenol exposure may be caused by the inhibition of the Wnt/β-catenin signaling pathway inhibited. In addition, the inability to catch food due to the abnormal development of the swim bladder may be the key to the death of zebrafish larvae during the mouth-opening stage.
丁香酚是一种从丁香中提取的天然酚类精油，具有镇痛和麻醉作用，广泛用于渔业麻醉。然而，大量使用丁香酚对水产养殖生产带来的潜在安全风险以及其在鱼类早期生命阶段的发育毒性一直被忽视。在本研究中，将受精后24小时（hpf）的斑马鱼（Danio rerio）胚胎暴露于浓度为0、10、15、20、25或30mg/L的丁香酚中96小时。丁香酚暴露延迟了斑马鱼胚胎的孵化，并降低了体长和鳔的充气率。丁香酚暴露组中死亡斑马鱼幼虫的累积数量高于对照组，且呈剂量依赖性。实时定量聚合酶链反应（qPCR）分析表明，丁香酚暴露后，在孵化和开口阶段调节鳔发育的Wnt/β-连环蛋白信号通路受到抑制。具体而言，Wnt信号通路抑制剂wif1的表达显著上调，而参与Wnt/β-连环蛋白通路的fzd3b、fzd6、ctnnb1和lef1的表达显著下调。这些结果表明，丁香酚暴露导致斑马鱼幼虫鳔无法充气可能是由于Wnt/β-连环蛋白信号通路受到抑制所致。此外，由于鳔发育异常导致无法捕食可能是斑马鱼幼虫在开口阶段死亡的关键。
