When is injury potentially reversible in a lung ischemia–reperfusion model?

Objective To verify the impact of ischemic time on lung cell viability in an experimental model of lung ischemia–reperfusion (IR) injury and its repercussion on lung performance after reperfusion. Methods Twenty-four animals were subjected to selective clamping of the left pulmonary artery and divided into four groups (n = 6) according to ischemic time: 15 (IR15), 30 (IR30), 45 (IR45), and 60 min (IR60). All animals were observed for 120 min after reperfusion. The hemodynamics, arterial blood gases measurements, and histologic changes were analyzed. Immunofluorescence assays for caspase 3 and annexin V were performed. Lipid peroxidation was assessed by thiobarbituric acid–reactive substances, and caspase 3 activity was assessed by colorimetric extract. Results The partial pressure of arterial oxygen significantly decreased at the end of the observation period in the IR30, IR45, and IR60 groups (P