The Protective Effect Of Propofol On Lung Injury Induced By Renal Ischemia-Reperfusion In Rat

IntroductionRenal ischemia - reperfusion( I/R) injury is one of the common pathophys-iology in clinic. Renal I/R can initiate a complex and interrelated sequence of events, resulting in injury of pulmonary. Now,the protective effect of propofol focus on the injury of I/R organ , but the effect on distant site injury is not clear-ly.In this study, we established the renal I/R injury model, and administrated propofol in different time. We investigated changes of MDA concentration, SOD activity and the histologic evaluation in various groups and further discuss their differences and relationship, providing theory basis for clinic application.Materials and Method1. Animal groupsTotal 48 Wister rats were randomly divided into 6 groups of C group ( sham -operated animals) , R group (renal I/R) ,P₁ group (administration of propofol at 1 hour before ischemia) , P₂ group (at the moment of ischemia) , P₃ group ( at the moment of reperfusion) , P₄ group( at 1 hour after reperfusion) . The renal I/R model were made through ischemia 45 min, followed by reperfusion for 24 hours.2. Specimen disposingAt the end of the reperfusion period, blood samples and lung tissues were collected. The blood samples were centrifuged to separate serum and RBC. Concentration of MDA in serum and the activity of SOD in RBC were measured.Each case of lung tissue was cut into four portions: one was fixed in 4% formaldehyde for light microscope. One was fixed in 2. 5% glutaraldehyde for electron microscope. The others were put into - 701 refrigerator for determining MDA concentration and SOD activity.3. Determination of SOD activity in RBC and lung tissuesSOD activity in RBC and lung tissues was measured with XO method.4. Determination of MDA concentration in serum and lung tissuesMDA concentration in serum and lung tissues was measured with TBA method.5. Light microscopeThe lung tissue was fixed in 4% formaldehyde and embedded in paraffin for H&E staining.6. Electron microscopeThe lung tissue was fixed in 2. 5% glutaraldehyde and embedded in epoxy resin.7. Statistical analysisAll values are expressed as mean ± SD. Statistical analysis was carried out using SPSS12. 0. Data was analyzed using one -way analysis of variance ( ANO-VA) . P less than 0.05 indicates statistic correlation, and P less than 0. 01 indicates significantly statistic correlation.Results1. SOD activity in RBC and lung tissues in various groupsCompared with group C, SOD activity significantly decreased in groups R and P4(P<0.01). Compared with group R , SOD activity was obviously increased in the groups which received propofol excluding group P4. Compared with group R, SOD activity significantly increased in groups Pjand P2 ( P <0. 01) and increased in group P3 (P < 0. 05 ) . Compared with groups P} and P2, SOD activity decreased in group P3 ( P < 0. 05 ) .2. MDA concentration in serum and lung tissues in various groups Compared with group C, MDA concentration significantly increased ingroups R and P4(P <0. 01). Compared with group R , MDA concentration was obviously decreased in the groups which received propofol excluding group P4. Compared with group R, MDA concentration significantly decreased in groups Pj and P2(P<0.01) and decreased in group P3 ( P < 0.05 ). Compared with groups P,and P2, MDA concentration increased in group P3(P<0.05).3. Light microscopelight microscopic findings in group R included inflammatory cells infiltration , capillary telangiectasia and thickening of the alveolar septa. The injured severity was obviously relieved in the groups which received propofol excluding group P4.4. Electron microscopeThe pulmonary ultrastructure was badly injured in group R. Transmission e-lectron micrograph shows the damage to the air — blood — barrier, the fragment of type I pneumocytes. The osmiophilic lamellar bodies in type II pneumocytes were evacuated. The injured severity was obviously relieved in the groups which received propofol excluding group P4.Conclusion1. Renal ischemia — reperfusion can lead to the injury of lung.2. Propofol can effectively protect pulmonary injury induced by renal ischemia - reperfusion.3. Different time in which propofol was administrated can influent on the protective function of propofol.4. Propofol not only can deactivate oxygen free radicals but also can inhibit the generation of oxygen free radicals. The prevent function is more important.