Phenotypic and transcriptomic consequences in zebrafish early-life stages following exposure to crude oil and chemical dispersant at sublethal concentrations

Xishan Li; Deqi Xiong; Zhonglei Ju; Yijun Xiong; Guanghui Ding; Guoxiang Liao

doi:10.1016/j.scitotenv.2020.143053

Phenotypic and transcriptomic consequences in zebrafish early-life stages following exposure to crude oil and chemical dispersant at sublethal concentrations

Sci Total Environ. 2021 Apr 1:763:143053. doi: 10.1016/j.scitotenv.2020.143053. Epub 2020 Oct 17.

Authors

Xishan Li¹, Deqi Xiong², Zhonglei Ju¹, Yijun Xiong³, Guanghui Ding¹, Guoxiang Liao⁴

Affiliations

¹ College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
² College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China. Electronic address: xiongdq@dlmu.edu.cn.
³ Department of Biological Chemistry, Grinnell College, Grinnell, IA 50112, USA.
⁴ National Marine Environmental Monitoring Center, Dalian 116023, China.

PMID: 33129528
DOI: 10.1016/j.scitotenv.2020.143053

Abstract

To further understand the underlying mechanisms involved in the developmental toxicity of crude oil and chemically dispersed crude oil on fish early-life stages (ELS), zebrafish (Danio rerio) embryos were exposed to GM-2 chemical dispersant (DISP), low-energy water-accommodated fractions (LEWAF), and chemically enhanced WAF (CEWAF) of Merey crude oil at sublethal concentrations for 120 h. We employed the General Morphology Score (GMS) and General Teratogenic Score (GTS) systems in conjunction with high-throughput RNA-Seq analysis to evaluate the phenotypic and transcriptomic responses in zebrafish ELS. Results showed that ΣPAHs concentrations in LEWAF and CEWAF solutions were 507.63 ± 80.95 ng·L^-1 and 4039.51 ± 241.26 ng·L^-1, respectively. The GMS and GTS values indicated that CEWAF exposure caused more severe developmental delay and higher frequencies of teratogenic effects than LEWAF exposure. Moreover, no significant change in heart rate was observed in LEWAF treatment, while CEWAF exposure caused a significant reduction in heart rate. LEWAF and CEWAF exposure exhibited an overt change in eye area, with a reduction of 4.0% and 25.3% (relative to the control), respectively. Additionally, no obvious impact on phenotypic development was observed in zebrafish embryo-larvae following DISP exposure. Significant changes in gene expression were detected in LEWAF and CEWAF treatments, with a total of 957 and 2062 differentially expressed genes (DEGs), respectively, while DISP exposure altered only 91 DEGs. Functional enrichment analysis revealed that LEWAF and CEWAF exposure caused significant perturbations in the pathways associated with phototransduction, retinol metabolism, metabolism of xenobiotics by cytochrome P450, and immune response-related pathways. Our results provide more valid evidence to corroborate the previous suggestion that ocular impairment is an equal or possibly more sensitive biomarker than cardiotoxicity in fish ELS exposed to oil-derived PAHs. All these findings could gain further mechanistic insights into the effects of crude oil and chemical dispersant on fish ELS.

Keywords: Chemical dispersant; Crude oil; Fish developmental toxicity; Zebrafish.

MeSH terms

Animals
Petroleum Pollution* / adverse effects
Petroleum* / toxicity
Transcriptome
Water Pollutants, Chemical* / toxicity
Zebrafish

Substances

Petroleum
Water Pollutants, Chemical