OBJECTIVETo investigate the protective effect of amrinone against experimental lung ischemia /reperfusion (I/R) injury.

METHODSTwenty-four Sprague-Dawley rats were randomly divided into 3 groups (n=8 each): sham- operated group, I/R group, and amrinone-treated I/R group (AMR group). The left lung of rats was subjected to ischemia for 90 minutes, followed by reperfusion for 2 hrs, to induce an I/R lung injury model. The rats of the AMR group received amrinone (10 mg/kg) intravenously 30 minutes before ischemia and 5 minutes before reperfusion. After 2 hrs of reperfusion, carotid artery blood was collected for blood-gas analysis and detection of serum levels of IL-1beta, IL-8 and TNF-alpha. The left lung was removed for detection of the lung wet/dry ratio, the erythrocuprein (SOD) activity and the malonaldehyde (MDA) content as well as the pathological changes.

RESULTSAfter 2 hrs of reperfusion, there were no significant differences in artery partial pressure of oxygen (PO2) and partial pressure of carbon dioxide (PCO2) among the three groups. The lung wet/dry ratio (5.3 +/- 0.5 vs 4.8 +/- 0.1) and the MDA content (0.66 +/- 0.16 nmol/mg prot vs 0.47 +/- 0.06 nmol/mg prot) in the I/R group were significantly higher than those of the sham-operated group (P <0.05). The administration of amrinone markedly reduced the lung wet/dry ratio (4.8 +/- 0.2) and the MDA content (0.51 +/- 0.09 nmol/mg prot) and increased the SOD activity (54.7 +/- 6.8 vs 39.3 +/- 3.0 U/mg prot) when comparing the I/R group (P < 0.05). The serum levels of IL-1beta, IL-8 and TNF-alpha in the I/R group were 22.08 +/- 3.85, 21.92 +/- 5.56 and 30.50 +/- 3.77 pg/mL respectively, which were significantly higher than those of the sham-operated group. The AMR group showed lower serum levels of IL-1beta, IL-8 and TNF-alpha (16.66 +/- 3.02,14.73 +/- 2.75 and 22.48 +/- 3.82 pg/mL, respectively) compared with the I/R group (P < 0.01). The pathologic examination displayed that the lung tissue structure was normal and there was no hyperemia in the sham-operated and the AMR groups. The lung tissue structure of the I/R group was nearly normal but there were hyperemia and more inflammatory cells than the sham-operated and the AMR groups.

CONCLUSIONSAmrinone has protections against lung I/R injury, possibly through its anti-oxidation effects and an inhibition of inflammation factors releasing.