Subanesthetic dose of isoflurane protects against zymosan-induced generalized inflammation and its associated acute lung injury in mice.

Multiple organ dysfunction syndrome (MODS) is one of the leading causes of death in the intensive care unit. Organ failure especially lung injury is highly associated with the mortality for MODS patients. Volatile anesthetic isoflurane (ISO) is one of the most widely used anesthetic agents, and ISO anesthesia has been reported to improve the survival rate and organ function in sepsis/MODS models. However, the application of anesthetic dose ISO in critically ill patients is limited. Compared with i.v. anesthetic pentobarbital treatment, we showed that twice inhalation of ISO at subanesthetic dose (0.7%, 0.5 minimum alveolar concentration) alleviated lung injury at 24 h after zymosan (ZY) injection and increased the 7-day survival rate from 10% to 45% in mice. We also showed that ISO exerted its protection by significantly improving the activities of superoxide dismutase and catalase in lung and serum when compared with those in pentobarbital-treated mice. The catalase inhibitor 3-amino-1, 2, 4-triazole partially abolished the protective effect of ISO in ZY-challenged mice. We conclude that subanesthetic dose ISO protects against ZY-induced generalized inflammation and its associated lung injury via enhancing the activities of antioxidant enzymes in mice, which may provide a new strategy for the treatment of critically ill patients.