肢体缺血预适应的小肠保护作用及与一氧化氮/内皮素-1的关系

目的：观察一氧化氮/内皮素-1(NO/ET-1)失衡与肢体缺血再灌注(I/R)后小肠损伤的关系，以及缺血预适应(IPC)对NO/ET-1系统的调节作用。 方法： 雄性Wistar大鼠18只，随机分为对照（control）组，缺血再灌注（IR）组和缺血预适应（IPC+IR）组，每组6只，分别测定血浆和小肠组织二氨氧化酶(DAO)、一氧化氮(NO)、内皮素-1(ET-1)、NO/ET-1比值的含量变化及小肠组织的髓过氧化物酶(MPO)、DNA双链百分率(ratio of DNA chain %)、总一氧化氮合酶（tNOS）、诱导型一氧化氮合酶（iNOS）、结构型一氧化氮合酶（cNOS）的水平；免疫组化法检测小肠组织的诱导型一氧化氮合酶（iNOS）、内皮型一氧化氮合酶（eNOS）的表达。 结果： IR组血浆和小肠组织NO、ET-1，血浆DAO及组织MPO均明显高于对照组，而 NO/ET-1的比值，组织DAO及DNA双链百分率明显少于对照组；小肠粘膜iNOS的表达及总NOS活性高于对照组，cNOS（主要为eNOS）的表达少于对照组。IPC+IR组血浆和小肠组织NO、ET-1，血浆DAO及组织MPO均明显少于IR组，而 NO/ET-1的比值，组织DAO及DNA双链百分率却明显高于IR组；小肠粘膜iNOS的表达及总NOS活性少于IR组，cNOS（主要为eNOS）的表达高于IR组。 结论： 肢体I/R后小肠损伤与NO/ET-1失衡有关，IPC对肢体IR继发的小肠粘膜损伤的拮抗作用可能通过对NO/ET-1系统的调节作用而介导，此时内皮源的NO产生增加，非内皮源的NO产生减少。

Protection of the limb ischemic preconditioning on the injury of gut is concerned with NO/ET-1 system in rats

AIM: To study the relationship between disturbance of nitric oxide/endothelin-1 (NO/ET-1) and the injury of gut following limb ischemia -reperfusion (I/R) in rats as well as the regulation of NO/ET-1 system by limb I/R preconditioning (IPC) . METHODS: A limb ischemia- reperfusion injury model in rats was established. The animals were randomly divided into three groups: control group, IR group and IPC group. The contents of diamide oxidase(DAO) , nitric oxide (NO) , endothelin-1 (ET-1) and ratio of nitric oxide/endothelin - 1 (NO/ET -1) in the plasma and the gut were measured. The leavels of myeloperoxidase, ratio of DNA chain (%), total nitric oxide synthase (tNOS) , inducible nitric oxide synthase (iNOS) and.constitutive nitric oxide synthase (cNOS) in the gut were determined. The expression of iNOS and endothelial NOS (eNOS) were detected by the immunohistochemical method. RESULTS: It was found that the levels of NO, ET-1 in the plasma and the gut tissue all increased after reperfusion, while the values of NO/ ET - 1 decreased. The values of DAO in the plasma and MPO in the gut increased, while the contents of DAO and the ratio of DNA chain ( % ) in the gut decreased. The expression of iNOS elevated, cNOS (mainly eNOS) reduced and total NOS increased. The protection of the limb IPC attenuated the disturbance of NO/ET - 1. CONCLUSION: The intestinal injury following limb I/R is related to the disturbance of NO/ET -1. The protection of the limb IPC might be conducted by its regulating NO/ET- 1 system. The endothelial NOS increases and non -endothelial NOS decreases in this situation.