Objective To observe the effects of melatonin on lung injury and NDRG2 ( N-myc downstream-regulated gene 2) expression after intestinal ischemia-reperfusion ( I/R) .Methods 40 healthy SD rats were randomly assigned to a sham group, an I/R group, a high-dose melatonin group ( 10 mg/kg) , and a low-dose melatonin group ( l mg/kg) . The model of lung injury was established by superior mesenteric artery clamping/unclamping. 30 minutes before clamping, melatonin was administered intraperitoneally to the rats in two melatonin groups, and normal saline in same volume was administered to the rats in the I/R group and the shamgroup. Then superior mesenteric arteries of the rats in the I/R group and two melatonin groups were clamped for 60 minutes. 45 minutes after unclamping, right lung tissues were sampled for pathological examination and wet/dry ( W/D) ratio measurement. The rats in the sham group underwent sham operation without clamping. The expression of NDRG2 protein in the lung tissue was detected by immunohistochemistry and Western-blot. Results Compared with the sham group, hemorrhage and inflammation of lung tissues were observed. The W/D was obviously increased and the NDRG2 expression was significantly decreased in the I/R group. Compared with the I/R group, mild hemorrhage and inflammation changes of lung tissues were observed and the W/D was decreased while the NDRG2 protein expression was increased significantly in two melatonin groups. There was no significant difference between two melatonin groups. Conclusion Melatonin may relieve lung injury after intestinal ischemia-reperfusion through up-regulating NDRG2 expression.
Objective To analyze the role of lienal polypeptide injection in acute lung injury induced by lipopolysaccharide (LPS) in rats. Methods Eighty male SD rats were randomly allocated into 4 groups: a LPS group, a control group, a lienal polypeptide group and a LPS+ lienal polypeptide group (20 rats in each group). Lienal polypeptide or normal saline was given with an intramuscular injection 30 min after an intraperitoneal injection of LPS (5 mg/kg). The severity of pulmonary injury was evaluated 4 h after LPS challenge by enzyme-linked immunosorbent assay (ELISA), wet-to-dry weight ratio, hematoxylin and eosin (HE) staining, TUNEL and Western blotting. Results Lienal polypeptide injection treatment significantly attenuated LPS-induced pulmonary histopathologic changes, alveolar hemorrhage, and neutrophil infiltration. Moreover lienal polypeptide injection significantly suppressed LPS-induced activation of metastasis-associated protein-1 (MTA1). Conclusion Lienal polypeptide injection is demonstrated to protect rats from LPS-induced acute lung injury by the expression of MTA1.