Study On The Toxicity Of Acenaphthene And Sulfoxaflor To Zebrafish Liver And Immunotoxicity Respectively

Zebrafish is an internationally recognized biological toxicological model.Zebrafish are similar to humans in hepatocyte composition,function,signaling and response to injury,as well as cellular processes that mediate liver disease,and most of the genome sequences and immune system of zebrafish are highly similar to humans.Therefore,zebrafish have broad application prospects in the research of immunology,liver,and other fields.In this study,the toxicological studies of acenaphthene and sulfoxaflor on zebrafish were carried out.Acenaphthene is a tricyclic polycyclic aromatic hydrocarbon that can accumulate in organisms leading to health risks.It has been reported that acenaphthene has acute toxicity to aquatic organisms,but studies on the hepatotoxicity of acenaphthene are lacking.In this study,we used zebrafish as a model to evaluate the effect of acenaphthene on the liver of zebrafish by enzyme activity and content determination,detection of reactive oxygen species,HE staining,PAS staining,oil red O staining,fluorescence quantitative PCR,immunohistochemistry and AO staining.Acenaphthene has been found to affect early development in zebrafish,manifested by delayed yolk sac absorption and shortened body length.Acenaphthene can promote ROS production and cause oxidative stress resulting in mitochondrial damage.The expression of genes related to inflammation and apoptosis was further detected.The results showed that the expressions of pro-inflammatory cytokines IL-8,TNF-α and IL-6 were up-regulated,the expressions of pro-apoptotic genes p53,Caspase-3,Bax and Bax/Bcl-2 were upregulated,and the expressions of anti-apoptotic genes Bcl-2 were down-regulated.In addition,we investigated the effects of acenaphthene on liver metabolism.Results showed that when exposed to acenaphthene,liver glycogen content decreased,lipid accumulation increased,and related indicators of liver metabolism changed significantly.In conclusion,acenaphthene results from mitochondrial damage through Ros-induced oxidative stress that activates inflammatory and apoptosis-related pathways leading to liver damage,and subsequently affects normal liver metabolism.Sulfoxaflor is an insecticide that is widely used and affects the nervous system of sucking pests and has been reported to be neurotoxic to bees and zebrafish.However,the immunotoxicity of sulfoxaflor has not been reported so far.In this study,zebrafish was used as the experimental model,and fluorescence quantitative PCR,detection of reactive oxygen species,AO staining,neutral red staining,sudan black staining,and western blot to assess the effects of sulfoxaflor on the immunotoxicity of zebrafish.The results showed that zebrafish embryos exposed to sulfoxaflor had increased mortality,growth retardation,the number of innate immune cells decreased significantly,the expression of apoptosis and pro-apoptotic genes increased significantly,and oxidative stress related indexes changed significantly.TLR4/NF-κB signaling pathway was further studied,the IL-6,IL-1β,COX2,TNF-α,TLR4,MYD88 genes expression were significantly up-regulated.In this study,we used small molecule inhibitor QNZ for rescue experiment,and detected the expression of relevant target proteins in QNZ signaling pathway.QNZ reduces the expression of TLR4/ NF-κB signaling pathway related protein NF-κB p65 in cytoplasm and nucleus and can rescue the number of innate immune cells.In summary,sulfoxaflor may induce immunotoxicity in zebrafish to some extent by activating TLR4/NF-κB signaling pathway.Acenaphthene and sulfoxaflor could induce hepatotoxicity and immunotoxicity in zebrafish through inducing oxidative stress,inflammation and apoptosis.This study provides new evidence for a more comprehensive understanding of the hepatotoxicity of acenaphthene and provides a basis for further research on the molecular mechanism of the effect of sulfoxaflor on aquatic ecosystems.