Toxic Effects Of Environmental Nanomaterials On Zebrafish(Danio Rerio) And Their Mechanisms

Since the 1970s years since the advent of nano materials,nano materials have been widely used,nano particles inevitably released into the environment,behavior of nano particles in the environment and potential risk is uncertain.What patterns of migration and transformation do the nanoparticles release in the environment and interact with each ecosystem?.The establishment of scientific evaluation and prediction system for ecotoxicity of nanomaterials is the key to the ecotoxicological effects of nanoparticles.In this study,we investigated the environmental toxicological effects of three environmental nanomaterials(Nano-Cu,Nano-C,Nano-TiO2)on zebrafish,and explored the mechanism of nanoparticles.The main research results are as follows:By model animal zebrafish,half lethal concentrations of three nanoparticles(Lethal,Concentration,50%,LC50)were established.Investigation of the toxic effects of three kinds of nano materials on zebrafish,found that three kinds of nano materials on zebrafish toxicity in half effect concentration were Nano-Cu 20.3363mg/L,Nano-C 175.0730mg/L,Nano-TiO2512.9100mg/L,the level of toxicity of three kinds of nano materials can be expressed as a sequence of Nano-Cu>Nano-C>toxicity grade Nano-TiO2 toxicity grade according to the rules of American Science Hospital,Nano-Cu is divided into Nano-C divided into moderate toxicity,toxicity,mild toxicity Nano-TiO2.According to the LC50 set up three kinds of nano materials challenge dose of Nano-Cu(0 mg/L,3 mg/L,3.90 mg/L,6.50 mg/L,10.80 mg/L,18,mg/L);Nano-C(0 mg/L,15.55 mg/L,25.92 mg/L,43.20 mg/L,72 mg/L,120 mg/L,Nano-Ti02(0);mg/L,25.92 mg/L,43.20 mg/L,72 mg/L,120 mg/L,200 mg/L).Pathological anatomy and pathological analysis,the subjects of zebrafish main organs of three kinds of nano materials in each dose group.The results show that with the increase of drug dose,zebrafish gill,liver,muscle and ovary tissue had obvious pathological changes,pathological changes in gill slightly swelling,hyperemia,gill gill fuzzy boundaries,gill fracture necrosis;gill cell pathological changes in gill cell swelling,nucleus cracking,vacuolar degeneration etc.The pathological changes of liver in zebrafish showed slight enlargement of hepatic sinusoid,congestion of hepatic sinusoid,slight blurring of hepatic sinusoid and partial necrosis of liver tissue;The change of liver cells is the dissolution or dissolution of hepatocytes,and the liver nuclei undergo severe deformation,atrophy and deviation from the cell center.Muscle by muscle tissue slightly swelling,clear boundaries,no significant pathological changes in muscle cells,slightly larger swelling,muscle cell gap narrowed,muscle cells between the muscle cells hyperemia,congestion and swelling,nuclear off part of the muscle cells,muscle boundaries blurred,swelling,part of muscle cable fault muscle cells,nuclear condensation,swelling,vacuolar degeneration,muscle necrosis and most muscle cable breaks,disorganized and blurred,muscle cell nucleus deformation,severe atrophy,deviated from the cell center,a large number of cell necrosis;Slightly loosely arranged among the oocytes in ovary tissue of zebrafish ovary in stage III,the decrease in the number of mature oocytes,oocytes arranged began to appear obvious loose phenomenon,deformation of swelling of mature egg stage oocytes,the degenerated oocytes,the oocytes were arranged in loose treatment group cells,severe deformation,showed that degeneration of oocytes increased,II and III cells accounted for the majority,basically no stage of mature oocytes.The pathological changes of zebrafish and test the infection dosage obvious relationship between the pathological changes caused by three kinds of nanomaterials toxicity in Nano-Cu,the most obvious changes and pathological changes occur early,pathological change with dose significantly,causing tissue necrosis and pathological changes of Nano-TiO2 Nano-C;moderate,pathological process caused by relaxation part of the tissue edema,hyperemia,swelling of cells.Based on the three kinds of nano materials in each dose group were the main biochemical indexes in zebrafish(GSH Glutathione glutathione,referred to as GSH),MDA(Malonic Dialdehyde,referred to as MDA),Na+K+-ATP ASE(Na+K+-ATP adenosine triphosphate sodium potassium adenosine three phosphatase,referred to as Na+K+-ATP ASE CAT From Micrococcus(Catalase),catalase,CAT detect).When the concentration of 0.00mg/L in zebrafish exposed Nano-Cu,3 mg/L,3.90 mg/L,6.50 mg/L,10.80 mg/L,18.OOmg/L,Nano-Ti02 concentration 0.00mg/L,15.55 mg/L,25.92 mg/L,43.20 mg/L,72.OOmg/L,120.OOmg/L,Nano-C concentration 0.00mg/L,25.92 mg/L,43.20 mg/L,72 mg/L,120.OOmg/L,200.OOmg/L,changes of the subjects of zebrafish in GSH,MDA,Na+K+-ATPase and CAT activity were measured,The results showed that Nano-Cu treatment group in zebrafish GSH content along with the concentration increase of the downward trend,the content of MDA increased with the concentration increased(P<0.05),the activity of Na+K+-ATPase increased as the concentration decreased significantly(P<0.05),the activity of CAT with the group concentration decreases show that the physiological activity of zebrafish influenced by Nano-Cu.The Nano-C group of zebrafish GSH content with the concentration of treatment groups decreased gradually,the content of MDA increased as the concentration increased,Na+K+-ATPase activity decreased with the concentration increased,the activity of CAT with the concentration of treatment groups decreased gradually,that influence the physiological activities of fish by zebra Nano-C concentration.The Nano-TiO2 group of zebrafish GSH content with the concentration of treatment groups decreased gradually,the content of MDA increased as the concentration increased significantly(P<0.01),the activity of Na+K+-ATPase increased with the concentration increased(P<0.05),the activity of CAT increased with the concentration treatment group decreased,the physiological activity zebrafish influenced by Nano-TiO2.The elemental distribution of nanoparticles in zebrafish was analyzed by energy dispersive X-ray spectroscopy(EDS).The results showed that copper and titanium were not detected in zebrafish.