Center for Drug Screening and Research, School of Geography and Environmental Engineering, Gannan Normal University, Ganzhou, 341000, Jiangxi, China; College of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou, 341000, Jiangxi, China.
Jiangxi Engineering Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases, Ji'an, Jiangxi, China; Jiangxi Key Laboratory of Developmental Biology of Organs, Ji'an, 343009, Jiangxi, China.
Ecotoxicol Environ Saf. 2020 Dec 1;205:111339. doi: 10.1016/j.ecoenv.2020.111339. Epub 2020 Sep 19.
Famoxadone-cymoxanil is a new protective and therapeutic fungicide, but little research has been done on it or its toxicity in aquatic organisms. In this study, we used zebrafish to investigate the cardiotoxicity of famoxadone-cymoxanil and the potential mechanisms involved. Zebrafish embryos were exposed to different concentrations of famoxadone-cymoxanil until 72 h post-fertilization (hpf), then changes of heart morphology in zebrafish embryos were observed. We also detected the levels of oxidative stress, myocardial-cell proliferation and apoptosis, ATPase activity, and the expression of genes related to the cardiac development and calcium-signaling pathway. After famoxadone-cymoxanil exposure, pericardial edema, cardiac linearization, and reductions in the heart rate and cardiac output positively correlated with concentration. Although myocardial-cell apoptosis was not detected, proliferation of the cells was severely reduced and ATPase activity significantly decreased, resulting in a severe deficiency in heart function. In addition, indicators of oxidative stress changed significantly after exposure of the embryos to the fungicide. To better understand the possible molecular mechanisms of cardiovascular toxicity in zebrafish, we studied the transcriptional levels of cardiac development, calcium-signaling pathways, and genes associated with myocardial contractility. The mRNA expression levels of key genes in heart development were significantly down-regulated, while the expression of genes related to the calcium-signaling pathway (ATPase [atp2a1], cardiac troponin C [tnnc1a], and calcium channel [cacna1a]) was significantly inhibited. Expression of klf2a, a major endocardial flow-responsive gene, was also significantly inhibited. Mechanistically, famoxadone-cymoxanil toxicity might be due to the downregulation of genes associated with the calcium-signaling pathway and cardiac muscle contraction. Our results found that famoxadone-cymoxanil exposure causes cardiac developmental toxicity and severe energy deficiency in zebrafish.
福美双·肟菌酯是一种新型的保护性和治疗性杀菌剂，但对其在水生生物中的毒性及其毒性机制的研究甚少。在本研究中，我们使用斑马鱼来研究福美双·肟菌酯的心脏毒性及其潜在机制。将斑马鱼胚胎暴露于不同浓度的福美双·肟菌酯中，直至受精后 72 小时（hpf），然后观察斑马鱼胚胎心脏形态的变化。我们还检测了氧化应激水平、心肌细胞增殖和凋亡、ATP 酶活性以及与心脏发育和钙信号通路相关的基因表达。福美双·肟菌酯暴露后，心包水肿、心脏线性化以及心率和心输出量的降低与浓度呈正相关。虽然没有检测到心肌细胞凋亡，但细胞增殖严重减少，ATP 酶活性显著降低，导致心脏功能严重不足。此外，胚胎暴露于杀菌剂后，氧化应激指标发生显著变化。为了更好地了解斑马鱼心血管毒性的可能分子机制，我们研究了心脏发育、钙信号通路和与心肌收缩力相关的基因的转录水平。心脏发育关键基因的 mRNA 表达水平显著下调，而与钙信号通路相关的基因（ATP 酶[atp2a1]、心肌肌钙蛋白 C[tnnc1a]和钙通道[cacna1a]）的表达显著受到抑制。主要心内膜血流反应基因 klf2a 的表达也受到显著抑制。从机制上讲，福美双·肟菌酯的毒性可能是由于与钙信号通路和心肌收缩相关的基因下调所致。我们的研究结果发现，福美双·肟菌酯暴露会导致斑马鱼心脏发育毒性和严重的能量缺乏。
