Protective effects of endothelin-1 receptor antagonist (BQ-123) against lung ischemia-reperfusion injury on the model of acute pulmonary embolism in rabbits

Abstract

Objective To explore the protective effects of endothelin-1 ( ET-1 ) receptor antagonist BQ-123 against ischemia-reperfusion injury after thrombolysis in acute pulmonary embolism.Methods Twenty-four big-ear Japanese rabbits (no limit of male or female) were divided into 4 groups randomly ( n =6 in each group):sham group ( sham-operated group),PE group ( pulmonary embolism group),UK group (thrombolysis group),BQ group ( UK + BQ-123 group).We detected the levels of ET-1 in the venous blood plasma and mean pulmonary arterial pressure (MPAP) before and 0.5,2,4 h after embolization.The ratio of lung tissue wet/dry (W/D),the superoxide dismutase (SOD) activity and malondialdehyde (MDA) content at the end of the experiment were measured.Results As compared with sham group [(18.92 ±0.63) mm Hg(1 mm Hg=0.133 kPa) ],the MPAP in PE group (19.01 ±0.60) mm Hg,UK group (20.14 ±0.85) mm Hg,and BQ group ( 19.79 ±0.78) mm Hg was increased significantly at 0.5 h after embolization (P ＜0.05).There was no significant difference in MPAP between BQ group and UK group at 2 h and 4 h after embolization.The levels of plasma ET-1 in BQ group were reduced more significantly than UK group at 4 h after embolization.As compared with sham group,the W/D and MDA content were increased,but SOD activity was reduced in PE group and UK group at the end of the experiment,and the same results were obtained between UK group and PE group (P ＜ 0.05).The W/D ratio and MDA content were lower,and SOD activity was higher in BQ group than in UK group (P ＜0.05).Conclusion Lung ischemia-repeffusion injury appeared in thrombolysis after acute pulmonary embolism,and BQ-123 may exert the antagonistic effets. Key words: Acute pulmonary embolism; Lung ischemia; Reperfusion injury; Endothelia; Endothelia receptor antagonist