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{L-End}Objective To investigate the effect of motorcycle exhaust (ME) on the level of oxidative stress in different parts of respiratory tract epithelial cells. {L-End}Methods BEAS-2B and A549 cells in logarithmic growth phase were randomly divided into control group, low- and high-dose groups. The two kinds of cells growing on the membrane of Transwell inserts were treated with air-liquid interface (ALI) exposure technique for 60 minutes. The cells in the low- and high- dose groups were treated with diluted gas with the volume ratio of ME to clean air of 1∶20 and 1∶10, respectively, while the cells in the control group were treated with clean air. Cells were collected to detect their relative survival rate using CCK-8 method after exposure. And the levels of malondialdehyde, glutathione and the activity of superoxide dismutase (SOD) of the cells were detected using colorimetry. {L-End}Results The ME exposure dose affected the relative survival rate of cells (P<0.01), which showed a downward trend with the increasing ME exposure doses (all P<0.05). However, there was no significant difference in the main effect of cell types and the interaction effect of ME exposure dose and cell type (all P>0.05). There was a significant interaction between ME exposure dose and cell type in the level of glutathione and the activity of SOD (all P<0.01), and the level of malondialdehyde was a significant main effect of cell type (P<0.01). There was no significant difference in the glutathione level and SOD activity between the low-dose group and the control group (all P>0.05), while the glutathione level and SOD activity in high-dose group were higher than those in the control group and low-dose group in BEAS-2B cells (all P<0.05). The glutathione level decreased with increasing ME exposure dose in A549 cells (all P<0.05). Compared with the control group, the low-dose group had a significantly higher activity of SOD (P<0.05) in A549 cells. The SOD activity of A549 cells in high-dose group was lower than those in control group and low-dose group (all P<0.05). The level of malondialdehyde in A549 cells was higher than those in BEAS-2B cells(P<0.05). {L-End}Conclusion ME exposure can lead to changes in the production of oxidative stress biomarkers in respiratory tract epithelial cells. The oxidative stress response induced by ME exposure varies among respiratory tract epithelial cells from different regions.
RESUMO
Objective@#This study aimed to use an air-liquid interface (ALI) exposure system to simulate the inhalation exposure of motorcycle exhaust particulates (MEPs) and then investigate the benchmark dose (BMD) of MEPs by evaluating cell relative viability (CRV) in lung epithelial BEAS-2B cells.@*Methods@#The MEPs dose was characterized by measuring the number concentration (NC), surface area concentration (SAC), and mass concentration (MC). BEAS-2B cells were exposed to MEPs at different concentrations @*Results@#Our results reveal that BMD of NC and SAC were estimated by the best-fitting Hill model, while MC was estimated by Polynomial model. The BMDL for CRV following ALI exposure to MEPs were as follows: 364.2#/cm @*Conclusion@#These results indicate that MEPs exposure