| Objective: To explore the optimal model of the postconditioning for lung ischemia-reperfusion injury in rats.Methods:42rats were randomly divided into7groups:normal group (S, n=6) only exposed hilus of the left lung;ischemia-reperfusion injury group (IR,n=6), reperfusion for120min of30min left-lung ischemia; Ischemia preconditioning group (IPC, n=6) submitted to three cycles of clamping and releasing the hilus of the left lung for five min before being submitted to the ischemia/reperfusion procedure; Ischemia postconditoning group (IPostC)-I (n=6) three successive cycles for15s reperfusion and15s occlusion before restoring full perfusion were performed; IPostC-11(n=6) three successive cycles for30s reperfusion and30s occlusion before restoring full perfusion were done; IPostC-III (n=6) three successive cycles for45s reperfusion and45s occlusion before restoring full perfusion were executed IPostC-IV (n=6) three successive cycles for60s reperfusion and60s occlusion before restoring full perfusion were done. The histopathologicai changes, wet/dry (w/d) weight ratio, apoptosis index were oberserved. The concentration of tumor necrosis factor a (TNF-α), STAT3, p-STAT3, interleukin-6(IL-6), interleukin-10(IL-10) in the lung injury tissue was measured by an enzyme linked immunosorbent.Results:1.Comparison among ischemia postconditioning:①Compared with group IPostC-11. the expression of IL-6, TNF-a, STAT3,apoptotic index,W/D were increased,but IL-10,phosphorylation of STAT3(p-STAT3) were reduced in group IPostC-I(p<0.05).There are no significant difference between group IPostC-1and group IPostC-Ⅲ, group IPostC-IV.②Compared with group IPostC-I, IPostC-III, group IPostC-IV, the expression of IL-6, TNF-a, STAT-3, apoptotic index, W/D were reduced, but IL-10, phosphorylation of STAT3(p-STAT3) were increased in group IPostC-II(p<0.05).③Compared with group IPostC-II, the expression of IL-6, TNF-a, STAT3, apoptotic index, W/D were increased, but IL-10,phosphorylation of STAT3(p-STAT3) were reduced in group IPostC-III(p<0.05).There are no significant difference between group IPostC-I and group, group IPostC-IV.④Compared with group IPostC-II, the expression of IL-6, TNF-a, STAT-3, apoptotic index, W/D were increased, but IL-10,phosphorylation of STAT3(p-STAT3) were reduced in group IPostC-IV(p<0.05). There are no significant difference between group IPostC-I and group IPostC-III.2.There are no significant difference between group IPostC-II and group IPC in the level of IL-6, IL-10, TNF-a, STAT3, phosphorylation of STAT3(p-STAT3) and the level of lung tissue apoptotic index, lung wet/dry.There are significant differences between group IPostC-II and group IR.3. Reserche of the morphology under microscopic:Compared the group IPostC-Ⅲ with the other postconditioning groups,the former shows the lightest extent of lung injury, a little inflammatory cell was infiltrated in lung interstitial. Group IPC and group IPostC-II are closer to the normal control group,so theirs lung injury degree are lightest.Conclusion:In the postconditioning model, the choice of30s as ischemia/reperfusion time interval is advisable and possible for protection of lung I/R injury. |
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