# Effects of Oxidized Pyrenes on the Biological Responses in the Human Bronchial Epithelial Cells
## 3 Results
### Effects of Pyrene and Its Quinone Forms on Airway Epithelial Cell Apoptosis and Necrosis  
No significant differences in cell death were observed after treatment with 3 uM pyrene, 4,5-PyQ, and 1,8-PyQ + 1,6-PyQ compared with that in the control. However, exposure to 4,5-PyQ increased the number of late apoptotic or necrotic cells, whereas exposure to 1,8-PyQ + 1,6-PyQ increased cell death compared to that in the control, even though the number of dead cells was greater after 4,5-PyQ exposure (Figure 2). Effect of Pyrene and Its Quinone Forms on IL-6, IL-8, and sICAM-1 Production by Bronchial Epithelial Cells  
We evaluated IL-6 production from BEAS-2B cells after exposure to 1, 3, and 10 uM pyrene, 4,5-PyQ, and 1,8-PyQ + 1,6-PyQ, and found no significant difference after exposure to 1 uM of all compounds compared with that in the control. At 3 uM, compared with  
Figure 1: Effects of pyrene and its quinone forms on the viability of human bronchial epithelial cells. Cells were treated with the specified concentrations of pyrene and its quinone forms for 24 h, and their viability was assessed using the WST-1 assay. The data are represented as the percentage of viability of the control treatment (0 umol/L) and are shown as the mean \(\pm\) standard error of the mean (SEM) from four individual cultures. **\(p<0.01\) vs. control, **\(\#\)\(p<0.01\)** vs. pyrene at the same concentration, \(\lx@sectionsign 8\lx@sectionsign p<0.01\) vs. each other. Figure 2: Effects of pyrene and its quinone forms on the apoptosis and necrosis of human bronchial epithelial cells. Dot-plot of flow cytometry, Q1, necrotic cells; Q2, late apoptotic or necrotic cells; Q3, early apoptotic cells; Q4, healthy cells. that in the control, IL-6 production was unaltered after pyrene exposure; however, IL-6 production decreased after 4,5-PyQ exposure (\(p<0.01\) vs. control) and increased after 1,8-PyQ + 1,6-PyQ exposure (\(p<0.05\)). At 10 \(\upmu\)M, IL-6 production increased after pyrene exposure, whereas it decreased after 4,5-PyQ and 1,8-PyQ + 1,6-PyQ exposure (\(p<0.01\)) compared to that in the control. The comparison of relative effects between the compounds revealed no significant difference in IL-6 production between any treatment condition at 1 \(\upmu\)M. At 3 \(\upmu\)M, IL-6 production after 4,5-PyQ exposure was lower than that after pyrene exposure (\(p<0.01\)), without any significant difference after 1,8-PyQ + 1,6-PyQ exposure (slight elevation). Furthermore, increased IL-6 production was observed after 1,8-PyQ + 1,6-PyQ exposure compared to that after 4,5-PyQ exposure (\(p<0.01\)). At 10 \(\upmu\)M, IL-6 production after treatment with 4,5-PyQ and 1,8-PyQ + 1,6-PyQ was lower than that after exposure to pyrene (\(p<0.01\)). No significant difference in IL-6 production was observed between the 4,5-PyQ and 1,8-PyQ + 1,6-PyQ exposure groups (Figure 3A). IL-8 production was assessed after treatment with 1, 3, and 10 \(\upmu\)M pyrene, 4,5-PyQ, and 1,8-PyQ + 1,6-PyQ, and no significant difference was observed after 1 \(\upmu\)M pyrene exposure compared with that in the control. However, cells treated with 4,5-PyQ and 1,8-PyQ + 1,6-PyQ showed lower IL-8 levels than the control (\(p<0.01\)). Similarly, there was no significant difference in IL-8 levels among cells treated with 3 \(\upmu\)M pyrene and 1,8-PyQ + 1,6-PyQ compared with those in the control; lower IL-8 levels were observed in 4,5-PyQ-treated cells (\(p<0.01\)). At 10 \(\upmu\)M, the IL-8 levels after pyrene exposure were similar to those in the control, whereas its levels decreased in the 4,5-PyQ- and 1,8-PyQ + 1,6-PyQ-treated cells (\(p<0.01\)). A relative comparison between compounds revealed that at 1 \(\upmu\)M, the 4,5-PyQ and 1,8-PyQ + 1,6-PyQ groups showed lower IL-8 levels than the pyrene group (\(p<0.01\)); in contrast, no significant differences were observed between the 4,5-PyQ and 1,8-PyQ + 1,6-PyQ groups.