In situ fluorescence staining of lung tissue showed that the expression levels of NLRP3 (P < 0.01 at P5 and P < 0.001 at P7) and Caspase-1 (P < 0.01 at P5 and P < 0.05 at P7) in the BPD group increased significantly at P5 and P7 (Fig. 3i–l), consistent with our western blot results. This evidence concerns the gene CASP1 and bronchopulmonary dysplasia.