Figure 4.

Immunoreactivity of 4-HNE. The 4-HNE immunostaining was mainly confined in the villous endothelium in villous tissues with hypoxia-reoxygenation (c,d, and e). Villous tissues immediately sampled after delivery (a), kept in medium equilibrated with 95% N₂/5% CO₂ for 2 hours (b), and experiencing 20 minutes of hypoxia, followed by 2 hours of reoxygenation with either 5% O₂/90% N₂/5% CO₂ (c) or air/5% CO₂ (d and e). Omission of the primary antibody served as the negative control (f). Scale bars: 200 μm (a–d, and f), 50 μm (e).