Study On The Dose-response Relationship And Time-effect Of Injury Induced By Silica Nanoparticles To Human Vascular Endothelial Cells

Objective: Occupational safety and health issues of nanomaterials are complex.Because nanomaterials are small yet have a relatively large surface area, they mayhave chemical, physical, and biological properties distinctly different fromlargerparticles of similar chemical composition. Those properties may affect the ability ofthe nanomaterials to reach the gas exchange regions of the lung, travel from the lungthroughout the body, penetrate dermal barriers, crosscell membranes, and interact atthe molecular level. Some preliminary research results show that the safety evaluationresult of micron grade material may not be applicable to nanoscale material, so thebiological safety of nanoscale materials issue receives people’s extensive concern.Therefore, Nanoparticles of silicon dixoide (Nano-SiO2) is choosed as a test substanceto do experiments in human vascular endothelial cells in vitro, with emphasis on theirdose and time effects.Methord: Nano-SiO2was selected as the test substances. The human umbilical veinendothelial cells (HUVECs) were exposed to the particles in different doses of0,5,10,25,50,100and200μg/ml for6,12,24and48hours. Then endothelial cellscytotoxicity was measured by CCK-8method and half inhibitory dose of cell wascalculated. Then the exposure doses were determined to be0,5,10,20,40μg/ml. Thecells were exposed to nano-SiO2in the dose as above for6,12,24and48hours. After exposure LDH, SOD, TNF-α and IL-6were measured.Results: It was observed that cell survival rate decreased with increasing doses andexposure time. If the exposure time is short, the cell survival rate began to obviouslydecrease in the group of higher doses. If the expose time is long, the survival ratebegan to decrease already in the lower dose.It was observed that LDH activity, TNF-α and IL-6production increased withincreasing doses and expoure time. Compared with blank control group, the dose atwhich TNF-α and IL-6production began to change significantly reduced with theincreasing exposure time, and vice versa; while the change of LDH activity did notshow such trend.The SOD activity increased with increasing doses when the cells exposed for6hourand12hour. The SOD activity increased at first and then decreased with increase indoses at the exposure time of24hour. The SOD activity decreased with increasingdoses at the exposure time48hour. With increasing exposure time, the SOD activityincreased at first and then decreased.Conclusion: Nanoparticles were able to exert certain toxic effect on HUVEC cells,and a positive relationship of dose-response and time-effect was observed.