Does Urinary Trypsin Inhibitor Have a Role in Acute Lung Injury Induced by Pulmonary Contusion

Abstract

We evaluate the efficacy of urinary trypsin inhibitor (UTI) on inflammation, oxidative stress, hypoxemia, and diseased lesion in a rat model of acute lung injury induced by blunt trauma. Rats were allocated to 4 groups. One group served as normal control. The other 3 groups had a moderate pulmonary contusion. Except for 1 sham group administrated saline, 1 group was administrated low-dose UTI (20,000 U/kg), and another group was administrated high-dose UTI (50,000 U/kg). Twelve hours after contusion, neutrophil counting in bronchoalveolar lavage fluid (BALF) was performed and tumor necrosis factor α level and albumin level in BALF was tested. Lung tissue malondialdehyde levels, superoxide dismutase, and catalase activity was investigated, and blood gas analysis and contusion volume quantification using 3-dimensional computed tomography were performed. High-dose UTI significantly decreased neutrophil count and tumor necrosis factor α level in BALF (P<0.05) and decreased albumin level in BALF but without significance. Lung tissue malondialdehyde levels was significantly reduced, whereas superoxide dismutase and catalase activity were elevated by UTI with significance (P<0.05) especially high-dose UTI. No statistical significance was seen in the change in arterial oxygen partial pressure (PaO2) and contusion volume by UTI (P>0.05). UTI has a dose-dependent trend to ameliorate inflammatory and oxygen stress in pulmonary contusion-induced acute lung injury. However, the effect on hypoxemia and contusion lesion and the best administration regime should be investigated in future study.