Neutrophil elastase ameliorates matrix metalloproteinase-9 to promote lipopolysaccharide-induced acute lung injury in mice 1

ABSTRACT PURPOSE: To investigate the regulatory roles of neutrophil elastase (NE) and matrix metalloproteinase-9 (MMP-9) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. METHODS: To construct LPS-induced ALI mouse models, wild-type C57BL/6 mice were administered 5.0 mg/kg of LPS through endotracheal, and/or 1.0 mg/kg of ONO-5046, and/or 20.0 mg/kg of chemically modified tetracycline-3 (CMT-3) by gavage. The levels of MMP-9, tissue inhibitor of metalloprotease-1, interleukin (IL)-6 were detected by real time RT-PCR at 6 h, 24 h and 48 h, and tumor necrosis factor (TNF), ...