Effects Of Different Doses Of Remifentanil On Expression Of VVEGF And ACE-mRNA For Lung Ischemia-reperfusion Injury In Rats

Objective: To explore the effects of different doses of remifentanil continuous infusionon ACE-mRNA expression of lung ischemia-reperfusion injury in rats and it’s possiblemechanism.Methods: Forty pathogen-free adult male SD rats weighing300～350g were randomlydevided into five groups（n=8each）: shamp operating group（group S）, model group（groupM） and different doses of remifentanil groups （group R1～R3）. Lung I/R model wasproduced by occlusion of the left hilum of lung for45min followed by120minreperfusion. Remifentanil was infused intravenously at a rate of0.2μg kg^-1 min^-1,0.6μg kg^-1 min^-1and1.2μg kg^-1 min^-1until120min of reperfusion after a loading doseof1μg kg^-1at15min before occlusion of the left hilum of lung in groupR1, R2and R3,respectively. The equal volume of normal saline was given in group S and M. The ratswere sacrified by exsanguinations at the end of reperfusion, the lung tissue was removedfor measuring lung wet/dry ration（W/D） and microscope examination, the lung injury wasevaluated by Smith lung injury score, the expression of ACE-mRNA was tested byRT-PCR.Results: Lung histologic examination demonstrated that the injury in group M wassignificantly more serious than that in the other four groups. Compared with group S,Smith lung injury score, W/D and the impression of ACE mRNA in lung tissure was allsignaficatly increased but group R1，P<0.01. Smith lung injury score,W/D and theimpression of ACE mRNA in lung tissure seems to be on decrease due to the rise of doseof remifentanil,P<0.05. Compared with group S, the concentration of VEGF in serum ofgroup M was all signaficatly increased（P<0.001or0.05）;Compared to group M, theconcentration of VEGF in lung tissue and serum was all reduced, but not the concentrationof VEGF in lung tissue in group R1（P>0.05）; the concentration of VEGF in lung tissueand serum seems to be on decrease due to the rise of dose of remifentanil, compared withgroup R1,the reduction of VEGF of lung tissue in group R2is not statisticallysignificant（P>0.05）,compared to group R2, the decrease of concentration of VEGF in lungtissue and serum in group R3is all not statistically significant（P>0.05）.Conclusion: Remifentanil definitely protect against LIRI,and correlated withdose,downgraded impression of ACE mRNA in pulmonary vascular endothelium andreducing the impression of VEGF may be one part of mechanisms of remifentanil inprotecting against LIRI.