Objective: To investigate the effect of ischemic preconditioning combined with α7 nAchR agonists on limb ischemia-reperfusion lung injury in rats.
Methods: Fifty healthy male Sprague-Dawley rats weighing 230-280 g were randomly divided into 5 groups: sham operation group (S, also means the control group), model group(M), model and ischemic preconditioning (IP) group, model and α7 nAchR agonists group (PNU) and model and united treatment (U) group. The model of lung injury was induced by 3 h of ischemia and 3 h of reperfusion. The arterial blood was collected at 3 h- reperfusion for blood gas analysis; The lung tissues were collected for determination of Pulmonary coefficient, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity and lung tissue inflammatory cytokines (IL-6 and TNF-a). The pathological changes of lung tissues were observed under light microscope, and the pathological score of lung tissue was conducted.
Results: Compared with S group, the PaO2, pH and the activity of SOD in lung tissue of M group at 3 h reperfusion were significantly decreased, Pulmonary coefficient, MDA,IL-6, TNF-a and pulmonary pathological score of lung tissue were significantly increased (P<0.05), the difference of PaCO2 was not statistically significant (P>0.05). Compared with M group, arterial PaO2and lung SOD activity of IP group, PNU Group, U group at 3 h-reperfusion decreased, while Pulmonary coefficient, lung group, MDA,IL-6, TNF-a and pulmonary pathological score of lung tissue were significantly increased (P<0.05), there was no statistically significant difference in pH and PaCO2 between the two groups (P>0.05). Compared with IP group and PNU group, PaO2 and SOD activity of lung tissue decreased in U group at 3 h reperfusion, Pulmonary coefficient, MDA, IL-6, TNF-a, pulmonary pathology scores of lung tissue increased (P<0.05). There was no significant difference in PH and PaCO2 between the two groups (P>0.05).
Conclusion: Ischemic preconditioning and α7 nAchR agonists can attenuate limb ischemia-reperfusion lung injury in rat to a certain extent, and the combined effect of the two is better than the separate application.