To determine whether Nintedanib, a tyrosine kinase receptor (TKR) inhibitor, could serve as a novel preventive strategy for BPD, we first examined dose-related effects of Nintedanib on the developing lung in neonatal rats and found that administration of high but not low dose Nintedanib impaired lung airspace growth and caused early death. This evidence concerns the gene NTRK1 and bronchopulmonary dysplasia.