Effects of sevoflurane preconditioning on expression of angiotensin converting enzyme mRNA in lung tissues during lung ischemia-reperfusion in rats

Objective To investigate the effects of sevoflurane preconditioning on the expression of pulmonary angiotensin converting enzyme (ACE) mRNA in lung tissues during lung ischemia-reperfusion (I/R) in rats.Methods Fifty-four male Sprague-Dawley rats,weighing 250-320 g,were randomly divided into 3 groups (n =18 each):sham operation group (group S),I/R group and sevoflurane preconditioning group (group SP).The animals were anesthetized,tracheostomized and mechanically ventilated.Lung I/R was induced by clamping the left pulmonary hilum for 45 min followed by 120 min reperfusion in groups I/R and SP.While the left pulmonary hilum was only isolated but not ligated in group S.2.1％ sevoflurane was inhaled for 30 min,and lung I/R was induced 10 min after the end of inhalation in group SP.Six rats in each group were chosen at 30,60 and 120 min of reperfusion and sacrificed,lungs were removed for determination of wet/dry lung weight (W/D) ratio,MPO activity (by colorimetric method) and the expression of ACE mRNA (by RT-PCR) and for microscopic examination in lung tissues.Results Compared with group S,the W/D ratio,MPO activity and expression of ACE mRNA were significantly increased in groups I/R and SP (P ＜ 0.05).Compared with group I/R,the W/D ratio,MPO activity and expression of ACE mRNA were significantly decreased in group SP (P ＜ 0.05).Microscopic examination showed that the pathologic changes were significantly attenuated in group SP compared with group I/R.Conclusion Sevoflurane preconditioning can reduce lung I/R injury through downing-regulating the expression of ACE mRNA in rats. Key words: Anesthetics, inhalation;  Reperfusion injury ;  Lung ;  Peptidyl-dipeptidase A ;  Ischemic preconditioning