MPO and bronchopulmonary dysplasia: In this study, we observed that hUC-MSCs significantly decreased the levels of these proinflammatory cytokines TNF-α, IL-1β, IL-6, and MPO and increased the expression of anti-inflammatory cytokine of IL-10 in the serum of BPD rats, which is consistent with the previous studies (33, 34), and probably suggests that inflammatory responses mediated by neutrophils, oxidative stress, and proinflammatory cytokines play an important role in the pathogenesis of BPD (35, 36).