Abstract:Objective To explore the effect of different doses of Parecoxib on expression of HO-1 and apoptosis in rat model of lung ischemia-reperfusion (IR). Methods Totally 40 male adult Sprague-Dawley rats were randomly divided into 5 groups: control group (group C), ischemia reperfusion group (group I/R), Parecoxib group (2?mg/kg, group L), parecoxib group (10?mg/kg, group M), and parecoxib group (20?mg/kg, group H). Pulmonary ischemia-reperfusion injury model was established by blocking the left hilum of lungs. The wet/dry weight ratio (W/D), MDA and MPO of lung tissues were measured. Apoptosis, histological morphology of lung tissue as well as the expression of HO-1 in lung were detected. Results MDA, MPO, W/D and apoptosis rate were increased significantly in group I/R when compared with those in normal group, which was attenuated by treatment of Parecoxib (P?0.05). There was no significant difference in MDA, MPO, W/D and apoptosis rate between group M and group H (P?>?0.05). Pulmonary injury was the most severe in group I/R, which was attenuated by different doses of Parecoxib in dose dependent manner. HO-1 was only slightly expressed in group C, while significant upregulation of HO -1 was detected in group I/R (P?0.05) and was further elevated with treatment of Parecoxib. There was no statistical significant difference in HO -1 between group M and H (P?>?0.05) Conclusions Parecoxib attenuates lung ischemia-reperfusion injury dose-dependently probably through increased expression of HO-1.