Neurodevelopmental Toxicity Of Nano-alumina To Zebrafish Larvae : Toxic Effects Of Particle Size And Ions

Objective:Nano-alumina is widely used in the fields of electronics,alloys and environmental new energy,so humans will inevitably come into contact with directly or indirectly to the nano-alumina and its by-products.Although nano-alumina is widely used,its toxicity is not fully understood,and the existing toxicological information is insufficient to comprehensively evaluate the toxic mechanism of nano-alumina.Therefore,this study aims to explore the mechanism of nano-alumina neurodevelopmental toxicity on zebrafish:particle size and ions toxicity.Methods:The 13 nm-Al and 50 nm-Al as the main research objects,the 13 nm-C and 50nm-C as the particle size control group,and dissolve Al³⁺as the ion control group.Al³⁺dissolved in the nano-alumina suspension was measured by ICP-MS.Using zebrafish embryo-larvae as the research model,the embryos 6 hours after fertilization were exposed to different exposure groups until 168hpf.In the process of exposure,different groups of larvae were photographed at different time points to observe the deformity.After exposure,the behavioral test,biochemical index test and gene test were carried out.Results:?1?According to ICP-MS measurement,Al³⁺was dissolved in the suspensions of 13 nm-Al and 50 nm-Al?100 mg/L?,which were?106.86±9.14??g/L and?102.82±7.03??g/L.?2?Malformation:At different stages of zebrafish larvae development,malformations occurred in the 13 nm-Al,50 nm-Al and Al³⁺groups,but no deformities in 1 3nm-C and 50 nm-C groups.?3?Impairment of athletic ability:In the particle size comparison experiment,the athletic ability of larvae in the 13 nm-Al and 50 nm-Al groups was weakened to varying degrees,and the smaller the particle size,the greater the impairment of athletic ability;In the particle size and ion comparison experiment,the decrease of the athletic ability of larvae in the 13 nm-Al and 50 nm-Al groups was mainly caused by the particle size factor,and the dissolved Al³⁺also contributed partly.?4?Decreased thigmotaxis:In the particle size comparison experiment,the13nm-Al and 50nm-Al group have decreased thigmotaxis to different degrees,and the smaller the particle size,the greater thigmotaxis damage.In the comparison experiment,the decline of thigmotaxis in the 13 nm-Al and 50 nm-Al groups was mainly caused by the particle size factor,and the dissolved Al³⁺also contributed partly.?5?Biochemical analysis:In the particle size comparison experiment,the SOD,LDH,and ROS in the 13nm-Al and 50nm-Al groups increased to varying degrees,and the smaller the particle size,the higher the SOD,LDH,and ROS levels;In the comparison experiments of particle size and ions,the increase of SOD,LDH,and ROS in13 nm-Al and 50 nm-Al groups was mainly caused by particle size factors,and the dissolved Al³⁺also contributed partly.?6?Effects on mRNA expression:In the particle size comparison experiment,the expressions of Beclin-1 and LC3-?in the 13 nm-Al and 50 nm-Al groups increased,and the smaller the particle size,the higher the expression level of beclin-1and LC3-II;In the comparison experiment of particle size and ions,the increase of Beclin-1 and LC3-?expression in the 13 nm-Al and 50 nm-Al group was mainly caused by particle size factor,dissolution Al³⁺also contributed partly.In the particle size comparison experiment,there was no significantdifference in the expression of Caspase-8 between the groups of 13 nm-Al and 50nm-Al.In the comparison experiment of particle size and ions,the decreased expression of Caspase-8 in groups of 13 nm-al and 50 nm-al was mainly caused by the dissolved Al³⁺.Conclusion:Nano-alumina can cause neurodevelopmental toxicity in the zebrafish embryo-larval stage,and nano-alumina also can reduce the average speed,distance and thigmotaxis of zebrafish larvae.The results also showed that the increase of SOD,LDH,ROS,the increase of Beclin-1,LC3-?expression and the decrease of Caspase-8 expression were all involved in the toxicity of nano-alumina to zebrafish embryo-larvae.This study comprehensively reported the possible mechanism of the particle size and ionic effects of nano-aluminum on zebrafish embryo neurodevelopmental toxicity,the mechanism of toxicity is not only the factor of the small size of nanoparticles,the dissolved Al³⁺ also contributes partly.