CASP9 and bronchopulmonary dysplasia: FADD is a downstream target of the IL‐17 signalling pathway and its expression was increased in clinical BPD lung tissue samples (Figure 6A); The expression of FADD was also increased in animal and cell that exposed to hyperoxia and was decreased by HBM‐Exo treatment (Figure 6B,C); Western blot also showed that the C‐Caspase 3 and C‐Caspase 9 was significantly up‐regulated after hyperoxia exposure, while they were significantly down‐regulated after HBM‐Exo treatment (Figure 6D).