The Toxicity And Its Mechanism Of ZnO Nanoparticles In HEK293 Cells

Zn O Nanoparticles are widely used in many aspects of life recently. The particle size of Zn O Nanoparticles is in nanometer scale which ranges from 1 to 100 nm. Due to the grain fine, the surface electronic structure and crystal structure changes, it has the surface effect, volume effect, quantum size effect and macroscopic tunnel effect, and high transparency, high dispersion, etc. With large advantage, it has a very broad application prospects widely used in rubber, ceramics, chemical industry, environmental protection, feed, electronics, cosmetics, optics, biology, medicine, and many other fields. Although Zn O Nanoparticles has created huge economic value, its toxicity and the health effects also should be aroused people’s concern.Based on this, in the study we use three different sizes of Zn O Nanoparticles(15 nm, 30 nm and 90 nm) as the object to research its toxic effects on HEK293 cells and to explore its mechanism of action. In the study we explore the effect of size and concentration of Zn O Nanoparticles on its cell toxicology. Finally, we hope that the result of our study can provide certain theoretical basis for its biological safety research in vivo.In the experiment, to begin with, Zn O Nanoparticles(15 nm, 30 nm and 90 nm) were characterized by transmission electron microscope(TEM) and dynamic light scattering(DLS). Then, the cell toxicity of Zn O Nanoparticleswere studied in HEK293 cells morphology, cell toxicity and the antioxidant index etc. The results show that the purity of the Zn O NPs used was greater than 99.9%, and the structure of Zn O NPs was zincite crystal shape. At the same time, the size is slightly larger than theory. Then in the morphology assay, we found that the morphology of treated HEK293 cells changed, shrinking into spherical shape and detaching from the surface forming clusters. Even, the toxicity of Zn O NPs has size-depend and concentration-depend effect. The results of MTT, flow cytometry instrument, Caspase3 test are in accordance with the result of morphology assay in size-depend and concentration-depend effect. HEK293 cells antioxidant index(MDA and ROS, GSH) test results showed that with the increase of concentration of Zn O NPs, MDA and ROS levels increased in HEK293 cells, but GSH level gradually reduce; However, with the decrease of the size of Zn O NPs, MDA and ROS levels increased in HEK293 cells, but GSH level gradually reduced. So, we suggest that excessive accumulation of ROS and GSH consumption affect the normal cell oxidation- antioxidant level, developing oxidative stress state, further inducing Caspase3 activation, resulting in cell apoptosis. It also indict that the toxicity of Zn O NPs is in size-depend and concentration-depend way. So, the toxic effect of Zn O NPs on HEK293 depend on its concentration and size, namely the higher the concentration of the Zn O NPs, the greater the toxicity of its in HEK293 cells, the smaller of the Zn O NPs size, the greater the toxicity of its in HEK293 cells.