Research of sevoflurane preconditioning combined with postconditioning on expression of angiotensin converting enzyme mRNA during lung ischemia/reperfusion in rats

Objective To investigate the effects of sevoflurane preconditioning combined with postconditioning on the expression of pulmonary angiotensin converting enzyme (ACE) mRNA in lung tissues during lung ischemia/reperfusion injury(I/RI)in rats.Methods Fifty-four SD rats were randomly divided into three groups,18 in each:sham operation group (S group),the left pulmonary hilum was only isolated but not ligated.Lung ischemia/reperfusion (I/R) group (I/R group),rats was induced by clamping the left pulmonary hilum for 45 min followed by 120 min reperfusion for preparing rat lung I/R model.Sevoflurane preconditioning combined with postconditioning group (Spr+o group),2.1％ sevoflurane was inhaled for 30 min,elution 10 min,the left pulmonary hilum was clamped for 45 min,and then perfusion was restored and the same time 2.1％ sevoflurane was inhaled for 30 min.Six rats in each group were chosen at 30,60 min and 120 min of reperfusion and sacrificed,lungs were removed for determination of wet-to-dry weight ratio (W/D),histological examination [by hematoxylin-eosin staining (HE)],the expression of malondialdehyde (MDA,by colorimetry method),endothelin-1 (ET-1) concentration in plasma [by enzyme-linked immunosorbent assay (ELISA)],the expression of ACE mRNA [by reverse transcription-polymerase chain reaction (RT-PCR)].Results Compared with S group,the W/D,the expression of ACEmRNA,ET-1 and MDA in rats were increased in groups Spr+o and I/R (P＜0.05).Compared with the I/R group,Spr+o group in reperfusion 30,60,120 min,the W/D were decreased significantly [(4.74±0.14) vs (5.01±0.05),(4.96±0.07) vs (5.18±0.10),(5.31±0.11) vs (5.53±0.20)](P＜0.05),ACE mRNA expression levels in reperfusion 30,60,120 min were also significantly decreased [(0.49±0.08) vs (0.70±0.09),(0.66±0.05) vs (0.82±0.07),(0.77±0.04) vs (0.92±0.04)] (P＜0.05),the ET-1 expression levels were decreased(P＜0.05) and in reperfusion 120 min was decreased significantly [(189±7) ng/L vs (280±13) ng/L] (P＜0.01),the MDA expression levels were decreased(P＜0.05) and in reperfusion 120min was decreased significantly [(3.69±0.17) μmol/L vs (5.01 ±0.14) μmol/L] (P＜0.01).Microscopic examination showed that the pathologic changes were significantly improved in Spr +o group compared with I/R group.Conclusions Sevoflurane preconditioning combined with postconditioning can reduce lung I/RI,which may be associated with downing-regulation of ACE mRNA. Key words: Sevoflurane;  Preconditioning;  Postconditioning;  Lung injury;  Angiotensin converting enzyme;  mRNA