Impacts Of Polystyrene Microplastics And F-53B On Zebrafish Immune System And Intestinal Microbial Diversity

The widespread existence of Microplastics(MPS)in the environment will not only damage the natural environment on which we live,but also pose potential risks to the health of animals in nature and even human beings.Because of its large surface area and strong hydrophobicity,microplastics can be adsorbed by organic pollutants in aquatic environment and serve as carriers of organic pollutants.With the increasingly serious environmental pollution caused by PFOS,the use of PFOS has been restricted or even banned in related industries at home and abroad.In order to meet the normal production demand,F-53 B,as a substitute for PFOS,will be continuously increased in both production and usage.During the production and use of F-53 B,it will inevitably flow to the environment and become organic pollutants,which will enter water,soil,air and other environmental media.Therefore,F-53 B in the presence of MPS in the water environment will inevitably lead to the co-existence of F-53 B and MPS.But at present,there is no research report on the compound pollution of microplastics and F-53 B at home and abroad.In this study,zebrafish as the research object,the immunotoxicity of F-53 B at concentrations of 0.001,0.01,and 0.1 96-h LC50 values for 96 h to zebrafish embryo and larvae was successively studied through exposure experiment,the toxicity of F-53B(10ng/mL)and PS-MPS(50 ng/mL)alone and combined exposure to larvae zebrafish,and the toxicity of F-53B(10 ng/mL)and PS-MPS(50 ng/mL)alone and combined exposure to adult zebrafish and effects on intestinal microbial diversity of adult zebrafish.(1)It was found that F-53 B had different degrees of toxicity to the development and immune system of zebrafish at different growth stages.It was found that acute exposure to F-53 B had significant differences in the mortality of zebrafish embryos and larvae,and the sensitivity of larvae to F-53 B was higher than that of embryo to F-53 B.The growth and development of larvae zebrafish were significantly inhibited after exposure to F-53 B.Through the analysis of immune-related biochemical indexes and gene expression,it was found that F-53 B had an effect on the immune response of both zebrafish embryos and larvae.In addition to the increase of ROS and NO content,the expression of many immunerelated genes were increased in both zebrafish embryos and larvae exposed group,but the number of maladjusted genes in zebrafish larvae was more than that in embryo.This suggests that F-53 B is more immunotoxic to zebrafish larvae than to embryos.(2)This study explored the effects of MPS on the bioaccumulation,oxidative stress and immune response of zebrafish larvae F-53 B.PS-MPS greatly promoted the adsorption of F-53 B,decreased the free solubility of F-53 B in the exposed solution,and reduced the biological enrichment of F-53 B in zebrafish larvae.Combined exposure to PS-MPS and F-53 B in zebrafish larvae is more likely to induce oxidative stress and inflammatory responses than the use of these two compounds alone.In addition,NF-κB signaling pathway may be involved in oxidative stress and inflammatory response induced by PS-MPS and F-53 B.(3)The intestinal microbial composition and inflammatory response related indexes of zebrafish were analyzed by high-throughput sequencing technology,and the effects of F-53 B and PS-MPS on intestinal microbial diversity and immunotoxicity of zebrafish were studied.The results showed that the presence of PS-MPS could reduce the bioaccumulation of F-53 B in various tissues(liver,gill,intestine and brain)of zebrafish,and weaken the degree of oxidative stress response of zebrafish when combined exposure occurred.Highthroughput sequencing of the V3+V4 region of 16 S rRNA showed that both single exposure to PS-MPS and combined exposure to F-53 B significantly changed the composition of intestinal microflora in zebrafish at the phlum level,while reducing the diversity of intestinal microflora in zebrafish.In this paper,zebrafish as a model biological system to study the compound toxicity of MPS and organic pollutants F-53 B,to provide a theoretical basis for a comprehensive solution to the impact of MPS and organic pollutants in water on aquatic organisms.At the same time,it provides practical guidance for the establishment of efficient pollution treatment technology of F-53 B and microplastics in the future to improve the environmental protection management system and reduce the pollution of F-53 B and microplastics from the root.