Effects of sevoflurane postconditioning on lung ischemia-reperfusion injury in rats

Objective To investigate the effects of aevoflurane postconditioning on lung iscbemia-reperfusion (IR) injury in rats and the mechanism involved. Methods Ninety-six male SD rots weighing 270-330 g were randomly divided into 4 groups (n = 24 each): sham operation group (group S), group IR, sevoflurane preconditioning group (group SPr), and sevoflurane postconditioning group (group SPo). The animals were anesthetized with intraperitoneal 10% chloral hydrate 400 mg/kg, tracheostomized and mechanically ventilated. Lung IR was produced by occlusion of the hilum of the left lung for 45 min and then it was unclamped for reperfusion, in group SPr, sevoflurane was inhaled at the end-tidal concentration of 2.1% 30 min before lung ischemia. In group SPo, sevoflurane was inhaled at the end-tidal concentration of 2.1% immediately before reperfusiun. Six rats from each group were sacrificed at 30 min, 1 h, 2 h, and 4 h of reperfnsion respectively. The TNF-α, IL-1 and IL-6 concentrations, and WBC count in broncho-alveolar lavage fluid (BALF) were determined.The percentage of PMN in WBC was calculated. The lungs were removed for determination of the cdntent of TNF-α, IL-1 and IL-6 in the lung tissues and microscopic examination. The apoptosis index (AI) was calculated by TUNEL assay. Lung injury was scored. Results The levels of TNF-α, IL-1 and IL-6 in lung tissues and BALF, AI, WBC count, percentage of PMN, and lung injury scores were significantly higher in group IR than in group S (P 0.05). Conclusion Sevoflurane postconditioning can protect the lungs from IR injury by decreasing the inflammatory reaction and inhibiting the apoptosis in pulmonary vascular endothelial and alveolar epithelial cells, and the effect is similar to that of sevoflurane preconditioning. Key words: Anesthetics, inhalation;  Reperfusion injury ;  Lung;  Ischemic postconditioning