Role of heme oxygenase-1 in endotoxin-induced lung injury in rats

【Objective】 To investigate the role of heme oxygenase-1(HO-1) in endotoxin-induced lung injury in rats. 【Methods】 Thirty-two male SD rats weighing 220 ~ 250 g were randomly divided into 4 groups(n =8): control group(group C), Zn PP-IX group(group Z), Zn PP- IX + LPS group(group ZL) and LPS group(group L). In the group Z and the group ZL, Zn PP- IX 10 μmol/ kg was given, isometric saline was given in the group C and the group L. Ten minutes later, LPS 5 mg/kg was given in the group L and the group ZL.The group C and the group Z respectively received isometric saline. The animals were killed at 6 h after LPS or normal saline administration. The lungs were removed for determination of W/D lung weight ratio, myeloperoxidase(MPO) activity, MDA content, SOD activity, expression of HO-1 and HO-1 m RNA. The severity of lung injury was evaluated using diffuse alveolar damage(DAD) score. 【Results】 Compared with the group C,W/D lung weight ratio, DAD score, MPO activity and MDA content were significantly increased, SOD activity was decreased, the expression of HO-1 and HO-1 m RNA up-regulated in the group L and the group ZL,while there was no significant difference in the above indices in the group Z. Compared with the group L, W/D lung weight ratio, DAD score, MPO activity and MDA content were significantly increased, SOD activity was decreased, while the expression of HO-1 and HO-1 m RNA down-regulated in the group ZL.【Conclusion】 HO-1 has protective effects on the lungs against endotoxin-induced acute lung injury in rats.