外源性NO在大鼠小肠缺血再灌注损伤中作用的实验研究

目的：了解外源性L－Arg在肠缺血再灌注损伤中的作用及其机制。方法：30只雄性Wistar大鼠随机分为5组，每组6只，肠系膜上动脉分离结束前10min静脉注射生理盐水2.0ml(C组），缺血前10min静脉注射生理盐水2.0ml( IR组），缺血前10min静脉注射L－Arg 200mg/kg(AIR组）；再灌注前10min静脉注射L－Arg 200mg/kg(IAR组）；再灌注前10min同时静脉注射L－Arg 200mg/kg和N－硝基L－精氨酸40mg/kg(INAR组）。120min实验结束后，所有动物取距回盲瓣5.0cm以上回肠肠断15cm，均分为3段，分别测定各组肠粘膜PMN浸润数量，MDA含量和粘膜组织学Chiu分级，另取36只大鼠随机分为生理盐水对照组和L－Arg实验组（再灌注前10min静脉L-Arg200mg/kg)，每组再随机分为3组，每组6只。两组分别与缺血前，缺血60min和再灌注60min取小肠中段肠管2.0cm，测定小肠组织线粒体内Ca^2 含量。结果：再灌注前给予适量的外源性L－Arg后，与C组相比，各组的肠粘膜PMN浸润数量，MDA含量，线粒体内Ca^2 含量和粘膜组织学均无明显差异（P＞0．05）；缺血前给予L－Arg后，与IR组相比，上述各项指标除Ca^2 含量外均明显减少（P＜0．05），但仍高于C组（P＜0．05）。结论 ：再灌注前给予外源性L－Arg对大鼠小肠缺血再灌注损伤具有明显的保护作用，缺血前给予L－Arg对肠粘膜损伤也能起到一定程度的保护作用。

Experimental study of the effect of exogenous L-Arginine on small intestinal ischemia reperfusion injury in rats

Objective: To study the effect of exogenous L-Arg on intestinal ischemia reperfusion and its mechanisms.Methods: Thirty Wistar rats were randomly divided into 5 groups(6 per group).The group venously injected with 2.0ml normal saline 10 minutes before the ending of superior mesenteric artery seperation(C).The group venously injected with 2.0ml normal saline 10 minutes before ischemia(IR).The group venously injected with L-Arg200mg/kg 10minutes before ischemia(AIR).The group venously injected with L-Arg200mg/kg 10minutes before reperfusion(IAR).The group venously injected with L-Arg200mg/kg and L-NNA40mg/kg 10minutes before reperfusion(INAR).15cm ileal segments were sampled 120minutes later and equally divided into 3 to determine the counts of mucosal PMN,content of MDA and mucosal histology scores.Thirty six rats were randomly divided into control and experimental groups(18 per group),each group was subdivided into 3 groups(6 per group).2.0cmileal segments were sampled before ischemia,60 ischemia and 60 reperfusion respectively to determine the counts of Ca 2+ in mitochondrion.Results: The difference between C and IAR was not significant(P>0 05),whereas AIR and IR was significant(P<0 05) .The effect of L-Arg venously injected before reperfusion was thorouly inhibited by L-NNA(an inhibitor of NOS).Conclusion: Exogenous L-Arg applied before reperfusion has remarkable protective effect on intestinal ischemia reperfusion in rats.Administration of L-Arg before ischemia also decreases to some extent the intestinal lesion induced by ischemia reperfusion