Fig. 4. Effects of lipopolysaccharide (LPS) insult in neutrophils precultured in normoxia-normoxia, hypoxia-normoxia, and hypoxia-hyperoxia conditions. Each value has been calculated as ratio (%) relative to control group. Compared to control group, hydrogen peroxide (H₂O₂) production was increased in all groups, apoptosis was delayed in all groups, and Toll-like receptor 4 (TLR₄) receptor production was increased in all groups. Mean ± standard deviation (n = 18). ^*P < 0.05, paired t-test.