Key Laboratory of Yangtze River Water Environment of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
Key Laboratory of Yangtze River Water Environment of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
Sci Total Environ. 2020 Sep 10;734:139227. doi: 10.1016/j.scitotenv.2020.139227. Epub 2020 May 7.
As a primary degradation by-product of tetracycline (TC), 4-Epianhydrotetracycline (4-EATC) has been detected frequently in the aquatic environment, which may pose a potential environmental risk to aquatic organisms. Up to now, however, the toxicology study on 4-EATC to aquatic organisms is limited. In the present study, in order to better understand the toxic mechanism of 4-EATC, developmental toxicity including lethal and sublethal effects of 4-EATC and TC were investigated. The results showed that the developmental toxicity of 4-EATC to zebrafish embryos was stronger than that of TC. The 96 h LC value of 4-EATC to zebrafish embryos was 29.13 mg/L. Malformations seemed to be the most sensitive sublethal endpoint of 4-EATC exposure, and the 96 h EC value was 8.57 mg/L. Transcriptome response of 4-EATC to zebrafish embryos was determined. The results showed that 430 different expression genes (DEGs) caused by 4-EATC, and most enriched in tryptophan (TRP) metabolism pathway. Annotation of DEGs in the TRP metabolism demonstrated that expression of 4 gene products in tryptophan metabolized along the kynurenine (KYN) pathway were changed. Disorder of TRP catabolism in KYN pathway was a potential mechanism of 4-EATC toxicity to zebrafish embryos.
作为四环素（TC）的主要降解副产物，4-差向脱水四环素（4-EATC）经常在水生环境中被检测到，这可能对水生生物构成潜在的环境风险。然而，到目前为止，关于 4-EATC 对水生生物的毒理学研究还很有限。在本研究中，为了更好地了解 4-EATC 的毒性机制，研究了包括致死和亚致死效应在内的 4-EATC 和 TC 对斑马鱼胚胎的发育毒性。结果表明，4-EATC 对斑马鱼胚胎的发育毒性强于 TC。4-EATC 对斑马鱼胚胎的 96 h LC 值为 29.13 mg/L。畸形似乎是 4-EATC 暴露的最敏感的亚致死终点，96 h EC 值为 8.57 mg/L。测定了 4-EATC 对斑马鱼胚胎的转录组反应。结果表明，4-EATC 引起了 430 个差异表达基因（DEGs），这些基因主要富集在色氨酸（TRP）代谢途径中。TRP 代谢中 DEGs 的注释表明，色氨酸代谢沿犬尿氨酸（KYN）途径的 4 个基因产物的表达发生了变化。KYN 途径中 TRP 分解代谢的紊乱是 4-EATC 对斑马鱼胚胎毒性的潜在机制。
