Cardiovascular Toxicity And Influencing Factors Of Nanoplastics On Zebrafish(Danio Rerio) Embryos

Microplastics（MPs）,especially nanoplastics（NPs）,could more likely to penetrate the cell membranes and impose adverse impacts on living organisms and human health.In this paper,the effects of functional group modification and exposure temperature on the toxicity of NPs were studied.Zebrafish embryos was used as the model organism for experimental simulation,and the effect of exposure temperature on the cardiovascular toxicity of NPs was studied.Their toxicity mechanism was analyzed using proteomic and metabolomic techniques.Firstly,positively charged amino modified polystyrene nanoplastics（PS-NH₂NPs）generally induced stronger toxicity than other functional group modified or unmodified NPs.For microorganisms,PS-NH₂NPs is more likely to bind to cell membranes and enter cells,causing cell membrane damage by producing reactive oxygen species（ROS）.Cell walls are negatively charged,and due to electrostatic interactions,positively charged NPs have a stronger effect on photosynthesis and plant growth inhibition in algae and plants than negatively charged NPs.PS-NH₂NPs enhance reproductive toxicity and genotoxicity of animals,reduce swimming performance of aquatic animals,destroy lysosome stability of animal or human cells in vitro,and cause cell damage.In addition,positively charged NPs generally adsorb more plasma proteins than negatively charged NPs,and are more likely to form protein crowns that are engulfed by phagocytes,reducing their toxicity.The aggregation of nanoparticles caused by the increase in temperature led to a shading effect and inhibited algal photosynthesis.The toxicity of nanoparticles to microorganisms and aquatic animals increases with the increase of temperature,which increases the ROS level of organisms and enhances the oxidative damage to organisms.The formation and composition of a protein corona affected by the elevated temperature and changes the toxicity of the nanoparticles.The results from our experiment reveals that PS-NH₂NPs can penetrate zebrafish embryo chorionic membrane at 24 hpf,and temperature increase promotes PS-NH₂NPs to penetrate chorionic membrane.The cardiovascular toxicity of NPs decreased when the exposure temperature increased.Transgenic zebrafish Tg（myl7:GFP）manifested that elevated temperature enhanced the cardiac contractility of larvae.This will damage mitochondrial together with the enhanced oxidative stress due to the elevated temperature,lead to energy metabolism disorder,and lead to increased mortality of zebrafish larvae.