ObjectiveTo explore the role of osteopontin (OPN) in hyperoxia-induced acute lung injury and its relationship with nuclear factor-κB (NF-κB),matrix metalloproteinase 2 and 9 (MMP-2,MMP-9). MethodsNinety-six mice were randomly divided into a phosphate buffer solution intranasal inhalation group (PBS group) and a recombinant OPN intranasal inhalation group. The mice were exposed in sealed cages >95% oxygen for 24-72 hours to induce lung injury or room air as control. The severity of lung injury was evaluated. The expression of NF-κB,MMP-2,MMP-9,TIMP-1 and TIMP-2 mRNA in lung tissue at 24,48 and 72 hours under hyperoxia were examined by reverse transcript-polymerase chain reaction (RT-PCR). Immunohistochemistry (IHC) was performed for detection of NF-κB protein in lung tissue. ResultsPBS group mice developed more severe acute lung injury at 72 hours under hyperoxia.TIMP-1 and TIMP-2 mRNA expressions were significantly increased in r-OPN group than their matched PBS group when exposed to hyperoxia. IHC study showed higher expression of NF-κB protein in lung tissue of PBS group at 72 hours of hyperoxia. ConclusionOPN can protect against hyperoxia-induced lung injury by inhibiting the expressions of NF-κB,MMP-2 and MMP-9.