The RT-qPCR results showed that miR-17 expression in lung tissues of hyperoxia + Hdac3−/− mice was higher than that in lung tissues of hyperoxia-induced BPD mice, but it was diminished in lung tissues of hyperoxia + Hdac3−/− + miR-17-antagomir-treated mice, which was similar to that in lung tissues of the BPD mice (Fig. 6a). The gene discussed is HDAC3; the disease is bronchopulmonary dysplasia.