硫化氢预处理对大鼠心肌缺血再灌注损伤的保护作用

目的:探讨硫化氢预处理对大鼠心肌缺血再灌注损伤的保护作用.方法:健康成年SD雄性大鼠40只,随机分成4组,每组10只.假手术组(S组)仅开胸并分离冠状动脉左前降支,不阻断血流150 min;缺血再灌注组(IR组)行冠状动脉左前降支阻断30 min,再灌注120 min;硫化氢预处理组(H组)予以静脉注射硫化氢钠0.05 mg/kg,给药后24h同IR组处理；硫化氢预处理+线粒体KATP通道阻断剂(5-羟葵酸,5-HD)组(D组)缺血前15 min静脉注射5-HD 5 mg/kg,其它同H组处理.再灌注结束后抽血测超氧化物歧化酶(SOD)、丙二醛(MDA)含量,测心梗面积,免疫印迹法测心肌S-腺苷蛋氨酸合成酶( S-adenosylmethionine synthetase,SAM-s)的表达.结果:心肌梗死面积与IR组(38.27％±5.64％)比,H组(25.40％±3.54％)减小(P＜0.05),D组(40.53％±5.24％)无明显差异(P＞0.05).心肌SAM-s表达与S组比,IR组、H组和D组均升高(P＜0.05)；与IR组比,H组降低(P＜0.05),D组无明显差异(P＞0.05).与IR组比,H组血清SOD的活性含量增高、MDA的降低(P＜0.05),D组无明显差异(P＞0.05).结论:硫化氢预处理对大鼠心肌具有保护作用,其机制可能是通过抑制心肌SAM-s表达,减少氧自由基的生成,增强心肌抗氧化能力有关.

Effects of hydrogen sulfide preconditioning on myocardial ischemia reperfusion injury in rats

Objective: To investigate the effects of hydrogen sulfide preconditioning on myocardial ischemia reperfusion injury in rats.Methods: Sprague-Dawley male rats were divided into 4 groups with 10 in each group:in S group rats received sham operation;in IR group rats were given with NS(1.0 ml/kg iv) 24 h before ischemia;in H group rats were treated with NaHS(0.05 mg/kg iv) 24 h before ischemia;and in D group,NaHS-treated rats received 5-hydroxydecanoate(5-HD) 15 min before ischemia.Rats in IR group,H group and D group were subjected to ischemia by occlusion of coronary artery for 30 min followed by 2 h of reperfusion.At the end of the reperfusion,myocardial infarct size was measured.SAM-s was measured by Western blotting.Plasma SOD activity and MDA were determined at the end of reperfusion.Results: The infarct size was significantly lesser in H group(25.40%± 3.54%) than that in IR group(38.27%±5.64%,P<0.05).The SAM-s protein expression in myocardium was significantly lower in H group than that in IR group.The plasma MDA content was significantly lower and SOD activity was higher in H group than those in IR group,but there was no difference between IR group and D group.Conclusion: The hydrogen sulfide preconditioning attenuates myocardial IR injury possibly through down-regulating SAM-s expression,reducing the production of oxygen free radicals and enhancing anti-oxidize effect in rats.