Nano/micro SiO₂Particles Induced Human Pulmonary Adenocarcinoma A549Cell Toxic Effects Research

Objective Nano-SiO₂due to its superior stability and its unique nature, medicine,cosmetics, petrochemical and other fields are widely used professional production andproduct use population increased. Micro-level SiO₂nature and typical pulmonary toxicantsknown industrial production, and its toxic effects on the lungs has been scientific proof, butwith the industrial development and wide application of nano-SiO₂, the crowd growingprobability of contact with particulate composite exposed micro and nanometer SiO₂composite exposure of the body to produce the pathway have yet to be thoroughly studied.Existing domestic and international studies have shown that nano-SiO₂from multiple levelsof toxic injury to the body so that the main role, and because of its special physical andchemical properties of target organs as the lung and spleen. Therefore, this study intends toexplore by in vitro cell culture nano/micro-SiO₂particles cytotoxicity of A549cells exposedindividual and composite indicators of inflammatory response and oxidative damage, lungcell death pathway further complement and improve the nano-SiO₂way and mechanism ofaction, and to provide a scientific basis for population health surveillance and diseaseprevention and control of nano-SiO₂contact.Methods Vitro cell culture, namely the establishment of human lung adenocarcinomacell line A549and micro/nano-SiO₂alone, composite exposure model. Reunion of the twokinds of particle size of nano-particles in the serum-free cell culture fluid, and its entering thecell form observed from the morphology by transmission electron microscopy （TEM）;exposure concentration of3.13μg/mL,6.25μg/mL,12.5μg/mL,25.0μg/mL,50.0μg/mL, 100μg/mL,200μg/mL MTT and CCK-8experimental quantitative determination of micro/nano A549cell proliferation activity and determine the follow-up test of the low,, thehigh-dose group; exposure concentration6.25μg/mL,25.0μg/mL and100μg/mL, respectiveLy,for the experimental low, medium and high dose groups, one-time exposure to24h afteroxidative damage indicators ROS and LDH testing to identify changes in the intracellularlevels of oxidative stress, which DCFH-DA statutory determination of particle theintracellular ROS quantitative determination of trace ELISA LDH levels in the cellsupernatant; supernatants were detected by ELISA. inflammatory response factor IL-6, IL-8and TNF-α levels change.SPSS18.0statistical software to analyze, the count data test, measurement data as mean±standard deviation （x±s）, each group with the control group AVONA test was used tocompare the two q test, p<0.05when you think that there is a statistically significantdifference （α=0.05）.Results1.Nano-SiO₂dispersed in solution conditions and enter the cell analysis: the two particlesize of nano-SiO₂showed reunion status in the culture medium, and is to reunite the statethrough the cell membrane and nuclear membrane, and cell damage caused by the cell.Themanner of death, including the two kinds of cell necrosis and apoptosis.2. Nano/micro-SiO₂cytotoxicity analysis: nano/micro separate or composite exposedA549cells can be made to cause injury （p<0.05）, and each exposure group showed a dose-response relationship （p<0.05）. Statistical analysis alone exposed group between the NanoGroup cytotoxicity greater than the same dose micro group （p<0.05）;30nano group than50nm group （p<0.05）; the composite exposure group higher than the same dose inhibition ofcell individual exposure group （p<0.05） trend.3. Nano/micro-SiO₂induced cellular oxidative damage analysis: each low, medium andhigh dose, nano/micro separate or composite exposure can be caused A549cells role of oxidative damage （p<0.05）. QuaLitative detection of LDH quantitative detection ofintracellular ROS visible groups ROS fluorescence intensity dose-response relationship;cells in the LDH levels in a dose-response relationship. Two indicators generally showed aseparately exposed to nano group cellular oxidative injury than the same dose micro group （p<0.05） between groups;30nm cells from oxidative injury than50nm group two particle sizeof nano-SiO₂particles compared to the same concentration high composite exposed group （p<0.05）; higher than the same dose of cells from oxidative injury alone exposed group （p<0.05）trend.4. Nano/micro-SiO₂induced inflammatory reaction: the low, high dose, nano/microseparate or composite exposure can cause inflammatory response of A549cell supernatantfactor IL-6, IL-8and elevated levels of TNF-α, and a dose-response relationship （p<0.05）.Three indicators overall are presented separately exposed to nano group cell supernatantinflammatory response level higher than the same dose micro group （p<0.05） between groups;compared to the two kinds of particle size SiO₂nanoparticles30nm group of cels, the sameconcentration inflammatory injury than50nm group of high （p<0.05）; the composite exposedcels inflammatory response was higher than the same dose alone exposed group （p<0.05）trend.ConcLusions1. Nano/micro-SiO₂particles separate or composite exposure can be caused by cellnecrosis and apoptosis are two ways the human lung adenocarcinoma cell line A549injury,inhibition of cell proliferation injury presented in organelles and the nucleus of the damage.Each group as a whole showed a dose-response relationship, separate exposure groupcytotoxic effect than composite exposed group, and showed the correlation of the particlesize.2. Nano/micro-SiO₂particles separate or composite exposure can cause oxidative stressfactor in human lung adenocarcinoma cell line A549and release of the inflammatory response factor, a role of oxidative damage and inflammatory injury. Each group as a whole showed adose-response relationship, separate exposure group of oxidative damage effects thancomposite exposed group, and presented a particle size correlation.3. SiO₂nanoparticles cause human lung adenocarcinoma cell line A549cell damage, onthe one hand may be intracellular oxidative stress and infLammatory cytokine release causedby the development of cell necrosis and apoptosis mitochondrial pathway. The other handwith the particulate matter to cause physical damage to reunite status of the cells in thebiofilm and organelles.4. SiO₂nanoparticles induced necrosis and apoptotic mechanisms and pathways arerequired further study.