Bovine milk-derived osteopontin attenuates hyperoxia-induced lung injury associated with NLRP3 inflammasome regulation in neonatal mice with bronchopulmonary dysplasia.

Background: Bronchopulmonary dysplasia (BPD) is a major complication of prematurity, and effective preventive strategies remain limited. This study aimed to investigate the protective effect of osteopontin (OPN) supplementation on hyperoxia (Hyp)-induced BPD and its underlying mechanisms. Methods: Newborn mice were randomly assigned to Control, Hyp, and Hyp + OPN groups. From postnatal day 0 (P0) to P14, mice were exposed to 21% or 75% O Results: Hyp exposure significantly inhibited body weight gain in newborn mice, leading to simplified alveolar structure, thickened alveolar septa, and impaired pulmonary vascular development. These changes were reflected by increased MLI, decreased RAC, reduced Ki67-positive cells, and fewer CD31-positive vessels. Hyp also induced a heightened inflammatory response, elevated oxidative stress levels, and increased expression of NLRP3 inflammasome-related molecules, accompanied by an increased number of TUNEL-positive cells. OPN intervention partially restored body weight, alleviated hyperoxia-induced lung pathological changes, improved morphometric parameters (decreased MLI and increased RAC), enhanced cell proliferation and vascular-associated changes, and reduced inflammation, oxidative stress, NLRP3 inflammasome activation, and the number of TUNEL-positive cells. Conclusions: Exogenous bovine milk-derived OPN supplementation alleviates hyperoxia-induced lung injury, partially improves alveolar and vascular-associated changes, reduces inflammatory responses and oxidative stress levels, and is associated with reduced expression of NLRP3 inflammasome-related molecules in a neonatal mouse model of hyperoxia-induced BPD. These findings support the potential of OPN supplementation as a candidate intervention strategy for BPD prevention and management.