Effect Of Sevoflurane Preconditioning On The Expression Of Autophagy Protein LC3 In Operated Lung Tissues Of Patients Undergoing One-lung Ventilation

Objective:As a common method of ventilation in thoracic surgery,one-lung ventilation can lead to the occurrence of hypoxemia because of the imbalance of ventilation/perfusion ratio and the increase of intrapulmonary shunt.Sevoflurane is a new type of halogen inhaled anesthetics,it is widely used in clinical anesthesia,a large number of studies have proved that sevoflurane preconditioning can protect the ischemia,hypoxia and ischemia-reperfusion injury of the important organs,such as heart,brain and lung,but the mechanism is unknown.As a self-stabilizing mechanism specific to eukaryotes,autophapy can maintain the homeostasis of the body and reduce injury by increasing its level rapidly when ischemia and hypoxia of cells,the deficiency of growth factors or the demand of high energy.Its research value has received wide attention.Therefore,the purpose of this research is to evaluate the effect of sevoflurane preconditioning on autophagy protein LC3 in operated lung tissues of patients undergoing one-lung ventilation.Methods:Forty patients,with ASA physical status ???,aged 30?80 yr,weighing 45?84 kg,scheduled for elective radical operation for lung cancer,were randomly divided into control group and sevoflurane preconditioning group which included 20 patients in each group.After a double-lumen tube was intubated and the position was checked by a fibreoptic bronchoscope,patients in sevoflurane preconditioning group were inhaled sevoflurane with the end-tidal concentration of 1.0 MAC for 30 min,followed by washout.The specimens for normal lung tissues around the cancer were collected to measure the expression of LC3-II protein by Western blot,and to evaluate pathologic damage by HE staining.In addition,one lung ventilation time,double-lumen tube and chest tube extubation time,hospital stay duration and the rate of pneumonia were compared between two groups.Results:Compared with that in control group,LC3-II in sevoflurane preconditioning group was significantly increased(P<0.05).However,the lung injury score has no significant changes between two groups(P>0.05).Moreover,there was no statistical difference in the time of one lung ventilation,double-lumen tube and chest tube extubation;hospital stay and the rate of pneumonia between two groups(P>0.05).Conclusion:The autophagy protein LC3 level in operated lung tissues of patients undergoing one-lung ventilation was up-regulated due to the preconditioning of sevoflurane,this mechanism may be involved in the lung protection effect.