Effects of dexamethasone administration at different times on intestinal ischemia-reperfusion injury and inducible nitric oxide syntlase activity in mice / 中华麻醉学杂志

ABSTRACT

ObjectiveTo evaluate the efffects dexamethasone (DEX) administration at different times on intestinal ischemia-reperfusion(I/R) injury and inducible nitric oxide synthase(iNOS) activity in mice.Methods Tirty-five healthy male Kunming mice weighing 20-24 g were randomly divided into 5 groups( n =7 each) Sham operation group (group Ⅰ ); intestinal I/R group (group Ⅱ ); DEX administration before ischemia group (group Ⅲ ); DEX administration during ischemia group ( group Ⅳ) and DEX administration at the begining of reperfusion group (group Ⅴ ).Intestinal I/R injury was induced by clamping the superior mesenteric artery for 30 min.Normal saline10 mg/kg,DEX 10 mg/kg was injected iv at 30 min before ischemia in groups Ⅱ and Ⅲ respectively.DEX 10 mg/kg was injected iv at 5 min of ischemia in groupⅣ and immediately at the begining of reperfusion in group Ⅴ.The mice were sacrificed at 3 h of reperfusion,and then the small intestinal tissues were taken for determination of intestinal pathological score( Chiu score),iNOS activity and nitric oxide (NO) content.ResultsChiu score was significantly higher in groups Ⅱ - Ⅴ,and iNOS activity and NO content were sinificantly higher in groups Ⅱ,Ⅳ and Ⅴ than in group Ⅰ ( P ＜ 0.05).Chiu score,iNOS activity and NO content were sinificantly lower in group Ⅲ,and were higher in group Ⅴ than in group Ⅱ ( P ＜ 0.05).There was no significant difference in the indexes mentioned above between groups Ⅱ and Ⅳ ( P ＞ 0.05).ConclusionDEX administration before ischemia can reduce intestinal I/R injury by inhibiting iNOS activity; DEX administration during ischemia has no effcet on intestinal I/R injury and iNOS activity; DEX administration at the begining of reperfusion aggravates intestinal I/R injury by enhancing iNOS activity.