The Experimental Research Of Postconditioning Against Small Intestines Ischemia/Reperfusion Injury

Objective:To study the protective effects of postconditioning against ischemia/referfusion injury of small intestine,the SD rats were divided into four group,Sham group, ischemia/reperfusion group,preconditioning group,postconditioning group,we conducted contrast research among the four groups,we investigate the effects of postconditioning on small intestinal ischemia/reperfusion injury by analyzing the intestinal mucous membrane's extent of damage and the inflammatory cell factor's release,to provide a new strategy for clinical prevention from small intestine ischemia/reperfusion injury.Methods:Fifty six SD rats weighed about 0.3kg,randomly were divided into four groups:Sham group,I/R group,IPC group,IPost group(n=14).Each group was divided into two subgroup according to time of reperfusion(n=7):①the S group:the rats underwent a 3cm medium length-wise laparotomy,exposure of the small intestine,identification and dissection of the SMA and then,closure abdominal cavity.②the I/R group:the rats were operated by occlusion of SMA for 45 min,and then,same with S group.③the IPC group:the SMA was subjected to 3 circles of 2min ischemia and 2min reperfusion before ischemia,and then,same with I/R group.④the IPost group:the SMA was subjected to 3 circles of 2min ischemia and 2min reperfusion before reperfusion,and then,same with I/R group.At the end of the operation,the rats were sacrificed,and dissected 10cm segment of ileum to determination of intestines mucous membrane's injury and measured small intestine wet/dry weight(W/D).The serum of TNF-a,IL- 1β,IL-6,IL-10 were measured by ELISA.Results:①the W/D ratio of I/R group,IPC group and IPost group are obviously higher than that of the S group from 2h to 4h(p<0.05),but the IPost group and IPC group are lower than that of the I/R group.There are no significant difference between IPost group and IPC group(p>0.05).②the changes of intestinal mucosa:in I/R group,the intestinal mucosa presented dilated and exposed capillaries and denuded villi,some of villi hemorrhage, ulceration,the lamina propria was edema and infiltrated with inflammatory cells. The intestinal mucosal structure maintain intact with lifting of the epithelial layer from the lamina propria and moderate extension of the subepithelial space in IPost group and in IPC group.In IPost group and IPC group,histopathologic scores were significantly lower than that of I/R group(p<0.05).There are no significant difference between IPost group and IPC group(p>0.05).③Compared with S group,the serum contents ofTNF-a,IL-1β,IL-6 in I/R group,IPC group and IPost group are obviously higher,but the IPost group and IPC are lower than that of I/R group,the contents of IL-10 in other three groups are lower than that of S group,and The IPost group and IPC group are higher than that of I/R group.There are no significant differences between IPost group and IPC group(p>0.05).Conclusion:①The IPost and IPC can reduce the W/D ratio of the reperfusion intestine,and alleviate small intestine of edema.②The IPost and IPC make small intestinal mucosa's extent of damage alleviated after reperfusion③The IPost and IPC can obviously inhibit the release of TNF-a,IL-1β,IL-6and promote anti-inflammatory medium of IL-10 expression.④The protection effects of ischemic postconditioning against ischemia/reperfusion injury in rat intestine are same as ischemic preconditioning.