烟碱预处理对大鼠心肌缺血-再灌注损伤的保护作用

Protective effects of Nicotine pretreatment against myocardial ischemia and reperfusion injury in rats

目的探讨烟碱预处理对大鼠心肌缺血-再灌注损伤的保护作用及其可能机制。方法 30只健康雄性Sprague-Dawlay大鼠,体重200～250g,随机均分为缺血-再灌组(I-R组)、烟碱预处理组(N组)、假手术组(Sham组)。测定三组血浆肌酸激酶同工酶(CK-MB)活性、丙二醛(MDA)含量和超氧化物岐化酶(SOD)活性,心肌组织中髓过氧化物酶(MPO)活性,电镜下观察缺血区心肌超微结构变化。结果与Sham组比较,I-R组血浆CK-MB活性、MDA含量及心肌组织MPO活性均升高、血浆SOD活性降低(P<0.05或P<0.01);与I-R组比较,N组血浆CK-MB活性、MDA含量及心肌组织MPO活性均降低,血浆SOD活性升高(P<0.05或P<0.01),心肌病理学损伤减轻。结论烟碱预处理可减轻大鼠心肌缺血-再灌注损伤,其机制可能与减少氧自由基生成、增强心肌抗氧化能力有关。

Objective To investigate the protective effect of nicotine against myocardial ischemia and reperfusion injury in rat. Methods Thirty male Sprague-Dawley rats weighting 200-250 g were randomly divided into three groups： ischemia and reperfusion injury group （group I-R）, nicotine 400 g/kg group （group N）, sham-operation （group Sham）. In sham group the anterior descending branch of left coronary artery was exposed but not occluded, in group I R the anterior descending branch of left coronary artery was occluded for 30 min followed by 90 nm reperfusion, in group N nicotion 400 g/kg was injection i. v. 30 rain before myocardial ischemia. At the end of 90 rain reperfusion the animals were killed and the hearts were harvested for histopathology change and MPO activity. MDA contents and SOD and CK-MB activity were detected. Results Myocardial ultrastrueture was well preserved in group N as compared to group I R. MDA contents and CK-MB and MPO activity were significantly increased in group I-R and nicotion 400 g/kg pretreatment significantly reduced that by I-R. SOD activity was significantly higher in group N than in group I-R. Conclusion Niction has cardioprotective effect on myocardium against I R in rats. Decrease in oxygen free radicals and increased antioxidant activity may be involved in the mechanism.