Effects Of Microplastics With Different Materials On Zebrafish Intestines And Its Health Risks To Human Beings

Microplastics are ubiquitous in the global environment,which will not only destroy the natural environment on which we live,but also pose potential risks to the health of animals and human beings.In this study,zebrafish(Danio rerio)was used as a model organism to investigate the toxic effects of two different types of microplastics,non degradable polyethylene terephthalate(PET)and degradable polylactic acid(PLA),on the intestinal tract of zebrafish.On this basis,16 S r RNA gene sequencing method and Tax4 Fun gene function prediction analysis method were used to discuss the possible human health risks caused by microplastics,which provided a reference for the study on the toxic effects and mechanism of microplastics and the potential risks to human healthThe accumulation and excretion of microplastics in the intestinal tract of zebrafish showed that microplastics with larger particle size were more likely to accumulate in the intestinal tract,while microplastics with smaller particle size were more likely to be discharged from the body.The abundance of PLA was significantly higher than that of PET,which was about 176 times that of PET microplastics.The simulation experiment of fish digestive juice found that PLA cracks appeared after being immersed in the simulated body fluids for 15 days,and the PLA infrared spectrum showed that the-OH characteristic peak generated by hydrolysis appeared,and the peak strength increased with the increase of time,which proved that PLA was more prone to degradation than PET.The results of intestinal tissue staining showed that both PET and PLA microplastics caused partial intestinal villus tip injury,decreased number of cup cells,and columnar epithelial cell abjection in the zebrafish intestines,and PLA caused more serious intestinal injury than PET.Both PET and PLA particle treatment significantly reduced the diversity of intestinal microorganism,and changed the dominant bacteria at the "phylum" level and "genus" level,and the PLA particle treatment group significantly changed the microbial community structure.The Tax4 Fun gene function prediction analysis showed that after PLA was stored in zebrafish intestinal tract for 15 days,the gene function of its intestinal flora was related to a variety of human diseases.Therefore,it can be inferred that long-term exposure and accumulation of microplastics may cause the occurrence of human diseases,thus causing certain health risks.