内源性一氧化氮在非创伤性缺血预处理中对兔肺的保护作用

目的探讨内源性一氧化氮（NO）在非创伤性缺血预处理（N—WIP）中对兔肺缺血／再灌注（I／R）损伤的保护作用及可能机制。方法采用N-WIP及经典缺血预处理（C-IP）的动物模型，比较两种缺血预处理方法中内源性NO对兔肺在缺血／再灌注损伤中的保护效应。将40只大白兔随机平均分为4组：对照组、I／R组、C—IP组和NWIP组。对比观察各组血清及肺组织中NO2^-／NO3^-、丙二醛（MDA）含量及超氧化物歧化酶（SOD）活性以及肺湿／干重比。结果N—WIP组和C-IP组的兔肺再灌注后NO2^-／NO3^-含量均高于I／R组（P〈0．01），甚至高于对照组（P〈0．05）。两种缺血预处理组SOD活性均高于I／R组（P〈0．01），肺湿／干重比和MDA含量均低于I／R组（P〈0．05，P〈0．01）。结论N-WIP与C-IP对移植肺在缺血／再灌注损伤中具有同等强度的保护作用。其机制可能是通过诱发内源性一氧化氮（NO）舒张血管，从而起到保护血管内皮的效应。

Protective effects of endothelia-derived nitric oxide on rabbit lung ischemia/reperfusion injury in non-traumatic ischemic preconditioning

Objective To investigate the protective effect of endothelia-derived nitric oxide(NO) on donor lung ischemia/reperfusion (I/R) injury in non-traumatic ischemic preconditioning(N-WIP) and the possible mechanism.Methods Two animal models of N-WIP and classical ischemic preconditioning(C-IP) were used and the protective effects of endothelia-derived NO on rabbit lung I/R injury were compared in those two IP methods.Forty New Zealand White rabbits were randomly divided into 4 groups(n=10 each): control group(C),I/R group,C-IP group,and N-WIP group.Lung injury was assessed by activities of superoxide dismutase (SOD),level of NO~-_2/NO~-_3 and malondialdehyde(MDA) and wet to dry weight ratio(W/D) in serum and lung tissues.Results The content of NO~-_2/NO~-_3 in serum and lung tissues in N-WIP group and C-IP group were both significantly higher than those in I/R group(P<(0.01)),even higher than in group C(P<(0.05)). The activity of SOD in two IP groups were both significantly higher than in I/R group(P<(0.01)). W/D and the levels of MDA in N-WIP group and C-IP group were significantly lower than in I/R group(P<(0.05),P<(0.01)).Conclusions Both N-WIP of hind limbs and C-IP of lung may have a similar protective effect against lung I/R injury. The mechanism may be related to pulmonary arterial endothelia-derived NO induced pulmonary artery relaxation to protect pulmonary vascular endothelial cells.