异丙酚对大鼠离体心脏缺血再灌注损伤的保护作用

Protective effects of propofol on myocardium against ischemia-reperfusion injury in isolated rat hearts

目的从氧化应激和线粒体介导的凋亡方面探讨异丙酚对大鼠离体心脏缺血再灌注损伤的保护作用。方法40只SD大鼠随机分为对照组、缺血再灌注(I/R)组和异丙酚15、30、60μmol·L-1组,每组8只。应用Langendorff离体心脏灌注系统建立心脏缺血再灌注损伤模型,经主动脉用Lock氏平衡灌注。除对照组外,各组均全心缺血25 min再灌注30 min。记录平衡灌注末、缺血前即刻及再灌注30 min时心率(HE)、左室收缩压(LVSP)、左室舒张末压(LVDEP)、左室压力变化速率(±dp/dtmax)、冠脉流量(CF);测定冠脉流出液中乳酸脱氢酶(LDH)、磷酸肌酸激酶(CK)活性及心肌线粒体活力、膜肿胀度、丙二醛(MDA)含量及心肌细胞凋亡率、半胱天冬酶(caspase)-3蛋白的表达。结果与I/R组比较,异丙酚30、60 μmol·L-1组再灌注30min时LVDEP升高,LVDP、±dp/dtmax、CF均降低,冠脉流出液中LDH、CK活性降低,心肌线粒体膜肿胀度、MDA含量降低,线粒体活力升高,心肌细胞凋亡率降低,caspase-3表达降低(P<0.05或0.01)。结论30、60/μmol·L-1异丙酚对大鼠离体心脏缺血再灌注损伤有一定的保护作用,减少缺血再灌所致的氧化应激,保护线粒体,抑制心肌细胞凋亡可能是其作用机制之一。

Objective To investigate the protective effects of different doses of propofol on the myocardium against ischemia-reperfusion （I/R） injury and the possible mechanism. Methods Healthy male SD rats weighing 250-300 g were anesthetized with intrapefitoneal pentobarbital 40 mg·kg^-1. Heparin 1000 IU·kg^-1 was given. The hearts were immediately removed and passively perfused with Lock＇ s solution aerated with 95% O2 ＋ 5% CO2 at 37℃ and constant pressure of 80 cm H2O in a Langendorff apparatus. Forty isolated hearts were divided into 3 groups： control group; I/R group in which the isolated hearts were made globally ischemic for 25 min followed by 30 min reperfusion and propofol group in which the isolated hearts were perfused with perfusate containing propofol 15, 30 or 60 μmol·L^-1 before ischemia and during reperfusion. The cardiac function variables including left ventricular developed pressure （LVDP）, the left ventricular end diastolic pressure （LVEDP） ± dp/dtmax, heart rate （HR）, coronary arterial flow （CF） were measured and recorded after equilibrium, before ischemia and at the end of 30 min reperfusion. The coronary outflow was collected and the lactate dehydrogenase （LDH）, creatine kinase （CK） activities were measured. At the end of reperfusion a piece of myocardium was obtained. The swelling and activity of and the content of malondialdehyde （MDA） in myocardial mitochondria were determined. The percentage of apoptotic cardiomyocytes was evaluated by flow cytometry and the expression of caspace-3 protein was detected by immuno-histochemistry. Results At the end of 30 min reperfusion LVDP, ± dp/dtmax, and CF were significant higher and LVEDP was significantly lower in propofol group （30, 60 μmol·L^-1） than in I/R group （P〈0.05 or 0.01）. LDH and CK activities in coronary outflow were also significantly lower in propofol group （30, 60 μmol·L^-1） than in I/R group （P〈0.05）. Perfusion with propofol 30 or 60 μmol·L^-1 before ischemia and during reperfusion significantly attenuated the increase in mitochondrial swelling and MDA content and the decrease in mitochondrial activity induced by I/R （P〈0.05）. The caspace-3 expression and percentage of apoptotic cardiomyocytes were significantly lower in propofol group （30, 60 μmol·L^-1） than in I/R group （P〈0.05 or 0.01）. Conclusion 30, 60 μmol·L^-1 propofol administered before ischemia and during reperfusion has cardioprotective effect. It can improve cardiac function impaired by I/R, attenuate I/R-induced peroxidation injury to mitochondria, down-regulate caspace-3 expression and inhibit cadiomyocyte apoptosis.