Western blotting results showed that, compared to the BPD group, the expression levels of HO-1 (P < 0.05) and Nrf2 (P < 0.05) in the lung tissue of newborn mice in the BPD + TBHQ group increased significantly at P5, whereas the expression of HO-1 (P < 0.01) and Nrf2 (P < 0.05) protein in the BPD + Nrf2−/− group was significantly inhibited (Fig. 5a–c). The gene discussed is HMOX1; the disease is bronchopulmonary dysplasia.