Effects of baicalin on pulmonary functions of acute respiratory distress syndrome induced by oleic acid in rats

Abstract

To investigate the effect of baicalin on pulmonary functions and its mechanism during the development of acute respiratory distress syndrome (ARDS) induced by oleic acid (OA) in rats. Rats were randomized into 5 groups: control, ARDS (OA induction, 0.12 mg/kg), baicalin-treated group (150 mg/kg), baicalin-treated group (300 mg/kg) and baicalin-treated group (450 mg/kg). The blood samples and lung tissue were collected at 10 min, 1, 2 and 6 h after OA injection. The lung concentration of myeloperoxidase (MPO) was detected by an ELISA (enzyme-linked immunosorbent assay) kit. Meanwhile, blood gas analysis and pulmonary pathological examination were also performed. The level of arterial oxygen partial pressure and oxygenation index decreased (P < 0.01 vs. control) and oxygenation index (190 mm Hg, 1 mm Hg = 0.133 kPa) reached the diagnostic standard of ARDS at 2 h in ARDS group. In baicalin-treated group (150 mg/kg and 300 mg/kg), the level of arterial oxygen partial pressure and oxygenation index increased versus the ARDS group. In baicalin-treated group (450 mg/kg), the level of arterial oxygen partial pressure was undifferentiated at 1, 2 and 6 h (P > 0.05) and decreased at 10 min (46.8 mm Hg, P < 0.05) versus the ARDS group. The level of MPO increased in baicalin-treated (300 mg/kg) and ARDS groups. Compared with the ARDS group, the level of MPO decreased significantly in baicalin-treated group (300 mg/kg) at 10 min, 1 and 2 h. Meanwhile, the pulmonary pathological damage improved in baicalin-treated group (300 mg/kg). An appropriate dose of baicalin may improve hypoxemia of ARDS induced by OA in rats. It may be due to the inhibition of MPO activity.