Experimental Study Of The Effect Of Intestinal Or/and Limb Ischemic Preconditioning On Intestinal And Lung Injury Induced By Intestinal Ischemic/reperfusion(I/R)

Background and ObjectiveThe studies found that intestinal or limb ischemic preconditioning had protective effect on the injury induced by intestinal ischemic/reperfusion(I/R), but the difference of the protective effect among intestinal ischemic preconditioning, limb ischemic preconditioning and combined ischemic preconditioning is now not known. The purpose of this study is to compare the effect of intestinal or/and limb ischemic preconditioning on the intestinal and lung injury induced by intestinal I/R, and to analyze its mechanism. Methods30 SD adult male rats were randomly divided into 5 groups(n=6): Sham group, ischemia/reperfusion group(I/R group), intestinal ischemic preconditioning group(LIPC group), limb ischemic preconditioning group(RIPC group), combined pretreatment group(Combine group). The following analysis was performed after 90 min of intestinal ischemia followed by 120 min of reperfusion in all groups:(1) the activity of serum diamine oxidase(DAO) and the contents of TNF alpha and IL-6 were detected;(2) the same 4.0-cm intestinal and the upper lobe of right lung were obtained, and the ratio of dry and wet weight of these tissues were measured;(3) a segment of 1.0 cm-intestine cut from 5cm to terminal ileum and the lower lobe of right lung were obtained, for detecting histopathological damage and apoptosis by HE staining and TUNEL methods,respectively;(4) the mucous membrane tissues of ischemic intestinal segment and the middle lobe of right lung were obtained and homogenated, the activity of SOD, MPO and contents of MDA in these tissue homogenate were detected. Results1. The DAO activity and the serum TNF-α and IL-6 levels in the other groups were significantly higher than that in sham group(P<0.05); The activity of DAO and the serum levels of TNF-α and IL-6 levels in the LIPC、RIPC and combined groups were significantly lower than that in I/R group(P<0.05); The DAO activity and serum TNF-α and IL-6 levels showed no statistical difference among LIPC, RIPC and combined group; 2. Compared with the sham group, the SOD activity of lung or intestinal tissue in the other groups decreased significantly(P <0.05), the histopathologic scores、apoptosis index、the ratio of dry/wet weight and MDA levels and MPO activity obviously increased; Compared with the I/R group, the SOD activity of lung or intestinal tissue in the LIPC、RIPC and Combined groups significantly increased(P<0.05), the histopathologic scores、apoptosis index、the ratio of dry/wet weight and MDA levels and MPO activity obviously decreased(P < 0.05);Compared with LIPC group, the ratio of dry/wet weight, MDA levels, MPO activity and SOD, histopathologic scores and apoptosis index of lung or intestinal tissue in the RIPC and Combined group had no statistical difference. Conclusion 1. Intestinal,limb and combined ischemic preconditioning had protective effect on intestinal and lung injury induced by intestinal ischemia/refusion, its mechanism may be related to resistance to oxidative stress, anti-inflammatory response and resistance to apoptosis. 2. The protective effect among intestinal, limb and combined ischemic preconditioning had no statistical difference.