Vaporized perfluorocarbon inhalation attenuates primary blast lung injury in canines by inhibiting mitogen-activated protein kinase/nuclear factor-κB activation and inducing nuclear factor, erythroid 2 like 2 pathway

Abstract

Blast lung injury is associated with high morbidity and mortality. Vaporized perfluorocarbon (PFC) inhalation has been reported to attenuate acute respiratory distress syndrome in humans and animal models. However, the effect of vaporized PFC on blast lung injury is still unknown. In this study, we investigated the protective effects and potential underlying mechanisms of action of vaporized PFC on blast lung injury in a canine model. This was a prospective, controlled, animal study in adult male hybrid dogs randomized to sham, blast (B), blast plus mechanical ventilation (B + M), and blast plus PFC (B + P) groups. All groups except for the sham were exposed to blast wave. The B + P group was treated with vaporized PFC for 1.5 h followed by 5.5 h mechanical ventilation. B + M group received 7.5 h mechanical ventilation and B group was observed for 7.5 h. Blast lung injury was induced using a shock tube. Blood gas, inflammatory cytokines, and oxidative stress were measured. Expression of nuclear factor (NF)-κB activation, mitogen-activated protein kinase (MAPK) and nuclear factor, erythroid 2 like 2 (Nrf2) were measured using western blot. Lung injury observed after blast exposure was marked by increased histopathological scores, ratio of lung wet to dry weight. PFC treatment attenuated blast lung injury as indicated by histopathological scores and ratio of lung wet to dry weight. PFC treatment downregulated interleukin (IL)-6, tumor necrosis factor (TNF)-α, and malondialdehyde (MDA), and upregulated superoxide dismutase (SOD) activity. PFC also suppressed expression of MAPK/NF-κB and Nrf2 protein levels. Our results suggest that PFC attenuated blast-induced acute lung injury by inhibiting MAPK/NF-κB activation and inducing Nrf2 expression in dogs.