Effects of simvastatin preconditioning on pulmonary heme oxygenase-1 expression in rats with lung injury induced by ischemia-reperfusion of hind limbs / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of simvastatin preconditioning on the pulmonary heme oxygenase-1 (HO-1) expression in rats with lung injury induced by ischemia-reperfusion (I/R) of hind limbs. Methods Forty-eight adult male SD rats weighing 250-300 g were randomly divided into 6 groups ( n = 8 each) sham operation group (group S) ; I/R group; I/R + simvastatin 1,5, 10 mg/kg groups (S1 , S2, S3 groups) ; simvastatin control group (group SC) . I/R of hind limbs was produced by occlusion of bilateral femoral arteries for 2 h followed by 3 h reperfusion. Croups S1 , S2 , S3 received simvastatin 1, 5, 10 mg/kg respectively via an oro-gastric tube for 3 days before I/R. Group SC received simvastatin 10 mg/kg via an oro-gastric tube for 3 days. Arterial blood samples were taken at 3 h of reperfusion for blood gas analysis and PaO2 and PaCO2 were recorded. The animals were then sacrificed and the lungs removed immediately for pathologic examination and determination of the wet/dry lung weight ratio (W/D ratio), superoxide dismutase (SOD) activity and polymorphonuclear neutrophil (PMN) count . Hie expression of HO-1 mRNA and protein in lung tissues was detected using RT-PCR and Western blot analysis respectively.Results Alveolar edema, localized pulmonary atelectasis and large amount of PMN infiltration were found in I/R group and were ameliorated in S1, S2, S3 groups. Compared with group S, PaO2 and PaCO2 were significantly decreased in I/R group, W/D ratio and PMN count were increased and SOD activity was significantly decreased in I/R, S1 , S2 groups, and expression of HO-1 mRNA and protein was up-regulated in the other five groups ( P ＜ 0.05). PaO2, PaCO2 and SOD activity were significantly increased, W/D ratio and PMN count were significantly decreased, and HO-1 mRNA and protein expression was up-regulated in S1, S2 and S3 groups as compared with I/R group ( P ＜ 0.05 or 0.01). W/D ratio and PMN count were gradually decreased, SOD activity was gradually increased, and HO-1 mRNA and protein expression was gradually up-regulated in S1, S2 and S3 groups. Conclusion Simvastatin preconditioning has protective effect against lung injury induced by I/R of hind limbs in rats through up-regulation of HO-1 expression in the lung tissues and in a dose-dependent manner.