ABSTRACT
Aim To investigate whether ulinastatin has a beneficial effect on lipopolysaccharide( LPS) induced acute respiratory distress syndrome ( ARDS ) in rats, and to explore the possible underlying mechanisms. Methods Fifty-six Wistar rats were randomly as-signed into control group, model group( LPS 6,12,24 h groups), ulinastatin group(UTI 6,12,24 h groups), with 8 in each group. ARDS rat model was reproduced by intraperitoneal injection of LPS ( 10 mg · kg-1 ) , The rats in UTI groups were injected ulinastatin (20 000 u·kg-1), The rats in the control group re-ceived an equal volume of normal saline at the same time, rats in each group were sacrificed at 6,12,24 hours after LPS challenge. Plasma and lung tissue sam-ples were collected, Histopathological evaluation, lung wet/dry (W/D) ratio, Tumor necrosis factor-a(TNF-α) , Interleukin-18 ( IL-18 ) , surfactant protein A ( SPA) , malondialdehyde ( MDA ) , nitric oxide ( NO ) and superoxide dismutase( SOD) were analyzed. Immu-nohistochemical method was performed to detect the protein expression of p38MAPK and ERK. Western blot method was used to detect lung phosphorylated p38 MAPK ( p-p38 MAPK ) and pERK protein expres-sion changes. Result In the control groups, lung tis-sue showed a normal structure and clear pulmonary al-veoli under a light microscope. In the model group, ARDS characters such as extensive thickening of the alveolar wall, significant infiltration of inflammatory cells, demolished structure of pulmonary alveoli, and hemorrhage were found. In the all UTI treatment groups, these pathological changes in lung were markedly alleviated compared with those of LPS-in-duced ARDS group. Compared with control groups, lung W/D ratio, tumor necrosis factor-a ( TNF-α) , in-terleukin-18 ( IL-18 ) and surfactant protein A ( SPA ) in plasma ,and lung MDA,NO levels in lung homogenates in the LPS group were increased significantly, while the lung SOD levels in the LPS group were decreased. Compared with the LPS group, lung W/D ratio, TNF-aIL-18 and ( SPAin plasma , and lung MDA levels in lung homogenates in the UTI groups were decreased significantly, while the lung SOD levels in the UTI groups were increased. Immunohistochemistry showed that positive expressions of p38 MAPK and ERK in cy-toplasm and nucleus in the ulinastatin treatment groups were significantly lower than those in the model group. Western blot showed that compared with the control group, the p-p38MAPK and pERK protein expression in LPS group were significantly increased, and the uli-nastatin could inhibit the protein expressions compared with model group. Conclusion Ulinastatin can signifi-cantly ameliorate the lung injury induced by LPS in rats via the intervention of p38 MAPK and ERK signa-ling pathway and reducing inflammation and antioxidant effect.
ABSTRACT
Aim To investigate the role of cAMP re-sponse element binding protein (CREB)in the injury of rat pulmonary microvascular endothelial cell (RPM-VEC)induced by LPS.Methods RPMVECs were i-solated and cultured in vitro,Western-blot was used to assay phosphorylation levels of CREB.Endothelial per-meability was determined by measuring the influx of Evans blue-labeled albumin across endothelial mono-layer.Results LPS increased CREB phosphorylation at Ser 1 3 3 in RPMVEC in a time-dependent manner , peaked at 30 min,but still higher at 120 min compared with basal control group.Pretreatment of cells with PKA inhibitor V5681 nearly suppressed the CREB phosphorylation stimulated in the presence of LPS,and the monolayer permeability of PMVEC was significantly increased. Conclusions LPS rapidly induces the phosphorylation of CREB in RPMVEC,and PKA me-diates the process.During the process of LPS-stimula-ted injury of RPMVEC,phosphorylation of CREB may play a protective role.