Transcriptome Analysis Reveals The Hepatotoxicity And Immunotoxicity In Zebrafish Embryos After Cyhalofop-butyl Exposure

AIM:To explore the hepatotxicity and immunotoxicity in zebrafish embryos after CyB exposure.Methods:We analysis the toxity in control and experimental group zebrafish embryos by transcriptome after CyB exposure.Results: Cyhalofop-butyl(CyB)has been used as the major herbicide for combating against annual rice grasses.However,due to easily transfer into aquatic environments,details of the adverse effects of CyB on aquatic organisms have not been fully understood.In this study,we systematically explored the toxic effects of CyB exposure on zebrafish embryos.Firstly,CyB markedly decreased the survival rate and caused a series of morphological malformations in a dose-dependent manner.Meanwhile,the area of liver and the number of innate immune cells such as macrophages and neutrophils decreased significantly upon CyB exposure.In addition,the levels of oxidative stress was greatly induced and the antioxidant enzyme activities such as CAT and SOD were elevated with the increase of CyB concentrations.Secondly,RNA-Seq identified 1,402 differentially expressed genes(DEGs)including 621 up-regulated and 781 down-regulated in zebrafish embryos after CyB exposure.KEGG pathway analysis revealed that metabolic pathways such as drug metabolismcytochrome P450,biosynthesis of antibiotics,and metabolism of xenobiotics were markedly enriched.GO functional analysis further suggested that oxidation-reduction process,reverse cholesterol transport,and triglyceride catabolic process were significantly enriched after CyB exposure.Besides,hierarchical clustering analysis proved that the genes involved in lipid metabolism,redox and immunity were mainly activated after CyB exposure.Finally,some of inflammatory cytokines and chemokines such as IL-1?,IL8 and IFN-? were obviously inhibited after CyB exposure under the TLR4-KD conditions.Conclusions:In summary,we performed a global survey of zebrafish embryos defense against cyhalofop-butyl exposure,and a large number of genes involved in lipid metabolism and innate immunity were acquired from RNA-Seq analysis.This study provides valuable informations for future elucidating the molecular mechanism of herbicide induced hepatotoxicity and immunotoxicity in aquatic ecosystems.