一氧化氮对肢体缺血预处理大鼠肢体缺血再灌注后肝损伤的保护作用

Protective effect of nitric oxide on hepatic injury of limb ischemia preconditioning following limbs ischemia reperfusion in rats

目的探讨一氧化氮(NO)在肢体缺血预处理(IPC)减轻大鼠肢体缺血再灌注后肝损伤中的作用。方法32只雄性Wistar大鼠随机分为对照组、肢体缺血再灌注组(LIR组)、肢体缺血预处理组(IPC组)和一氧化氮合成酶抑制剂L-NAME组(L-NAME组),每组8只。对照组不阻断双后肢血流;LIR组以橡皮带阻断双后肢血流4 h后恢复血流灌注4 h;IPC组预先阻断双后肢血流5 min后恢复血流灌注5 min,反复4次后操作同LIR组;L-NAME组操作同IPC组,于松带前15 min静脉滴注L-NAME。分别测定各组大鼠血浆NO、内皮素-1(ET-1)、丙二醛(MDA)、谷丙转氨酶(ALT)、谷草转氨酶(AST)及肝组织NO、ET-1、MDA、髓过氧化物酶(MPO)含量和DNA双链百分率。结果与对照组比较,LIR组血浆NO、ET-1、MDA、ALT、AST含量和肝组织NO、ET-1、MDA、MPO含量均升高(P<0.05),DNA双链百分率下降(P<0.05);与IPC组比较,LIR组和L-NAME组血浆ET-1、MDA、ALT、AST含量和肝组织ET-1、MDA和MPO含量均升高(P<0.05),血浆及肝组织NO含量和DNA双链百分率下降(P<0.05);L-NAME组与LIR组比较各指标差异无统计学意义(P>0.05)。结论 NO参与了肢体IPC对大鼠LIR后肝脏的保护效应,可能与NO抑制了ET-1的缩血管作用有关,也可能与减少白细胞过度聚集活化和减弱脂质过氧化有关。

Objective To evaluate the possible role of nitric oxide （NO） in the protective effect in limb ischemia pre- conditioning on hepatic injury following hind limbs ischemia reperfusion in rats. Methods Thirty-two male Wistar rats were divided into control group,limbs ischemia-reperfusion （LIR） group,limb ischemia preconditioning（IPC） group and L-NAME group,8 rats in each group. The bloodflow of double hindlimbs was not occluded in control group. The blood flow was occluded by rubber straps for 4 hours and restored reperfusion for 4 hours in LIR group. In IPC group ,the blood flow was occluded for 5 minutes and restored for 5 minutes which was repeated four times in advance, the remaining operation was similar to LIR group. The operation was similar to IPC group in L-NAME group except an intravenous drip of L-NAME before restoring. The changes of NO, endothelin-1 （ ET-1 ）, malondialdehyde （ MDA）, alanine transaminase （ALT） and aspartate transaminase （AST） in plasma were observed. The contents of NO, ET-1, MDA, myeloperoxide （MPO） and the ratio of DNA chain in liver were measured. Results Compared with control group, the levels of NO, ET-1, MDA, ALT, AST in plasma and the contents of NO, ET-1, MDA, MPO in liver increased（ P 〈 0.05 ）, the ratio of DNA chain in liver decreased in LIR group （P 〈 0.05 ） ;compared with IPC group,the levels of ET-1, MDA, ALT, AST in plasma and the contents of ET-1, MDA and MPO in liver increased（P 〈0.05） ,NO in both plasma and liver and the ratio of DNA chain in liver decreased（P 〈0.05）. There was no significant difference in above indexes between L-NAME group and LIR group （P 〉 0.05 ）. Conclusion NO perhaps participates the pro- tection effect of LIR on hepatic injury following limbs ischemia repeffusion in rats, the possible role is related to restrain the ac- tion of ET-1, improving the aggregation of neutrophil and alleviating the damage of the lipid peroxidation.