RESUMO
<p><b>OBJECTIVE</b>To investigate the effect of short and long term exposure to SiO2 nanoparticles on microRNA expression level in human bronchial epithelial cells(16HBE cells).</p><p><b>METHODS</b>The 16HBE cells were exposed to 5, 10, 15, 20, 25, 30 and 40 μg/ml SiO2 nanoparticles for 24 h to detect the cell viability by using CCK-8 assay. The inhibition rate of proliferation activity and half inhibitory concentration (IC50) were calculated. The 16HBE cells were exposed to 10 μg/ml SiO2 nanoparticles for 10 and 30 generations, named P10 and P30, and the control P0 was set. The cells were treated with SiO2 nanoparticles at 0, 1/4 IC50, 1/2 IC50 and IC50 concentration and μm-SiO2 at IC50 concentration for 24 h, and the control serum-free culture medium was set. Agilent miRNAs microarray chip was used to screen differentially expressed miRNAs in P10, P30 and P0 groups. The expression level of miRNA was detected by reverse transcription fluorescence quantitative polymerase chain reaction (qRT-PCR).</p><p><b>RESULTS</b>The inhibition rate of proliferation activity of 5, 10, 15, 20, 25,30,40 μg/ml group were (-3.33 ± 3.80)%, (20.40 ± 11.73)%, (39.08 ± 5.53)%, (55.10 ± 5.78)%, (66.42 ± 9.60)%, (71.67 ± 7.34)%, (81.43 ± 5.37)%, respectively; F=129.11, P<0.001. The IC50 (95%CI) was 18.35 (15.82-20.72) μg/ml. The expression level of miRNA-494-3p in P0, P10 and P30 were 1.00, 0.45 ± 0.08, 0.28 ± 0.07, respectively; F=60.77, P<0.001. miRNA-19a-3p were 1.00, 2.27 ± 0.45, 1.06 ± 0.19, respectively; F=30.05, P<0.001. miRNA-148b-3p were 1.00, 1.78 ± 0.29, 0.88 ± 0.19, respectively; F=30.23, P<0.001. Compared to control group, the expression level of miRNA-494-3p in 5, 10, 20 μg/ml SiO2 nanoparticles groups and 20 μg/ml μm-SiO2 group were 0.99 ± 0.04, 1.38 ± 0.19, 2.13 ± 0.14, 0.81 ± 0.25, respectively; F=57.03, P<0.001. miRNA-19a-3p were 0.91 ± 0.03, 1.12 ± 0.03, 0.53 ± 0.01, 0.86 ± 0.01, respectively; F=408.78, P<0.001. miRNA-148b-3p were 0.95 ± 0.02, 1.22 ± 0.00, 0.54 ± 0.02, 1.15 ± 0.04 respectively; F=264.14, P<0.001.</p><p><b>CONCLUSION</b>Short and long term exposure to SiO2 nanoparticles can affect the expression level of miRNAs in 16HBE cells. The expressions of miRNA-494-3p after long and short period exposure are different.</p>