MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China.
MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China.
Ecotoxicol Environ Saf. 2017 Jan;135:40-47. doi: 10.1016/j.ecoenv.2016.09.011. Epub 2016 Sep 27.
Humic acid (HA) is a major component of dissolved organic matter, is ubiquitous in the aquatic environment and influences the biological toxicity of organic pollutants. In this study, we investigated the cytochrome P450 1A (CYP 1A) mRNA expression and ethoxyresorufin-O-deethylase (EROD) activity in the gills and liver of zebrafish following exposure to the s-triazine herbicide prometryn with or without HA present. Prometryn induced both CYP 1A mRNA expression and EROD activity. The CYP 1A mRNA expression of zebrafish that were exposed to a combination of prometryn and HA was increased compared to those exposed to prometryn alone. A likely cause for CYP 1A induction is the impact of special components of HA, functioning as aryl hydrocarbon receptor (AHR) agonists. In combination with HA, these increase prometryn levels in tissues. Similar results for EROD activity were evident. In our time course study, CYP 1A mRNA expression reached maximum values during 24h. This revealed CYP 1A mRNA transcription as a comparatively sensitive toxicity index. In a recovery experiment, we found a faster decrease of CYP 1A mRNA expression to control levels (CK) in gills compared to liver tissue. Following exposure to HA, CYP 1A mRNA expression in liver tissue displayed a faster decrease to CK levels. HA induced enhanced metabolic rates for prometryn. In contrast, recovery regularity of CYP 1A expression in gills was independent of the presence of HA. This result indicates different detoxification mechanisms for HA in liver and gills.
腐殖酸（HA）是溶解有机物质的主要成分，在水生环境中无处不在，会影响有机污染物的生物毒性。在这项研究中，我们研究了三嗪除草剂普草津单独或与腐殖酸一起暴露后，斑马鱼鳃和肝脏中细胞色素 P450 1A（CYP 1A）mRNA 表达和乙氧基荧光素-O-脱乙基酶（EROD）活性。普草津诱导了 CYP 1A mRNA 表达和 EROD 活性。与单独暴露于普草津的斑马鱼相比，同时暴露于普草津和腐殖酸的斑马鱼的 CYP 1A mRNA 表达增加。CYP 1A 诱导的一个可能原因是腐殖酸的特殊成分作为芳香烃受体（AHR）激动剂的影响。与腐殖酸结合后，这些成分会增加组织中的普草津水平。EROD 活性也有类似的结果。在我们的时间过程研究中，CYP 1A mRNA 表达在 24 小时达到最大值。这表明 CYP 1A mRNA 转录作为一种相对敏感的毒性指数。在恢复实验中，我们发现鳃组织中 CYP 1A mRNA 表达更快地恢复到对照水平（CK），而肝组织则较慢。暴露于腐殖酸后，肝组织中 CYP 1A mRNA 表达更快地恢复到 CK 水平。HA 诱导了普草津代谢率的提高。相比之下，HA 对鳃组织中 CYP 1A 表达的恢复规律没有影响。这一结果表明，HA 在肝脏和鳃组织中的解毒机制不同。
