Hyperbaric oxygen preconditioning protects lung against hyperoxic acute lung injury in rats via heme oxygenase-1 induction

•HBO-PC ameliorated the biochemical and histological lung alterations induced by hyperoxia.•HBO-PC decreased oxidative products but increased antioxidant enzymes.•HBO-PC up-regulated HO-1 mRNA and activity.•HO-1 inhibitor abolished the protective effects of HBO-PC. Hyperoxic acute lung injury (HALI) is a clinical syndrome as a result of prolonged supplement of high concentrations of oxygen. Previous studies have shown hyperbaric oxygen preconditioning (HBO-PC) had a protective effect on oxidative injury. In the present study, we investigated the effect of HBO-PC on HALI in rats. The results demonstrated that HBO-PC ameliorated the lung biochemical and histological alterations induced by hyperoxia, decreased oxidative products but increased antioxidant enzymes. Furthermore, HBO-PC up-regulated heme oxygenase-1 (HO-1) mRNA and activity in lung tissues. The administration of HO-1 inhibitor, Zinc protoporphyrin IX, abolished its protective effects. The data showed that HBO-PC could protect rats against HALI and the anti-oxidative effect may be related to the up-regulation of HO-1.