Abstract: OBJECTIVE To evaluate the effect of dexmedetomidine on autophagy protein LC3 in operated lung tissues during one lung ventilation in patients undergoing radical operation for lung cancer. METHODS Forty-six patients scheduled for elective radical operation for lung cancer (ASA physical status Ⅰ-Ⅱ), were randomly divided into control group and experimental group. Each group included 23 patients. Before induction of anesthesia, dexmedetomidine was infused at a rate of 1.0 μg·kg^-1over 15 min, followed by continuous infusion at a rate of 0.5 μg·kg^-1·h^-1 until 30 min before the end of operation in experimental group; meanwhile the equal volume of normal saline was given in control group. At four time points, including immediately after one-lung ventilation(T₁), at 30 min(T₂) and 60 min(T₃)of one-lung ventilation, and at the end of operation(T₄), arterial blood samples were collected for blood gas analysis and oxygenation indices were calculated. Plasma concentrations of tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) were measured by ELISA method. The specimens for normal lung tissues around the cancer were collected to measure the level of LC3 protein expression by Western blot and the ratio of LC3-Ⅱ/LC3-Ⅰwas calculated. RESULTS Compared with control group, plasma concentrations of TNF-α and IL-6 were significantly decreased, the ratios of LC3-Ⅱ/LC3-Ⅰand oxygenation indices were significantly increased (P<0.05) in experimental group. Moreover, there were no statistical difference in the time of one lung ventilation, blood loss and the time of tracheal tube extubation between two groups. CONCLUSION Dexmedetomidine can enhance autophagy in the operated lung tissues and mitigate inflammatory responses, improving pulmonary function during one lung ventilation in patients undergoing radical operation for lung cancer.