外源性磷酸肌酸对离体鼠心能量代谢及线粒体功能的影响

Effect of Exogenous Creatine Phosphate on Energy Metabolism and Mitochondrial Function in Isolated Rat Hearts

目的 应用改良离体做功鼠心模型 ,探讨外源性磷酸肌酸 (CP)抗心肌缺血再灌注损伤的作用机制。方法将 72只鼠分为 5组 ,将 5组 L angendorff灌注鼠心在 37℃下缺血 40分钟后恢复灌注 2 0分钟。A组不灌注 St.Thom as液 ;B组和 C组于缺血开始灌注 St.Thomas液 ,C组的 St.Thom as液中加入 CP(10 mmol/L ) ;D组和 E组于缺血 15分钟后灌注 St.Thomas液 ,E组的 St.Thomas液中加入 CP(10 mm ol/L)。测定心脏做功指数、冠状动脉流量、心肌三磷酸腺苷 (ATP)和丙二醛 (MDA)含量以及尼克酰胺腺嘌呤二核苷酸 (NADH)的动态变化 ;进行线粒体半定量分析和心肌超微结构观察。 结果 E组复灌后心脏做功指数和冠状动脉流量分别高于 D组 (P<0 .0 5 ) ,同时心肌 ATP含量增高 (P<0 .0 5 ) ;B组与 C组比较无差异 ;C组和 E组复灌后 MDA,NADH分别较 B组和 D组下降 (P<0 .0 5 ) ,且缺血末 ATP与复灌 2 0分钟 MDA的生成无相关关系 ;而 B组和 D组呈负相关 (r=- 0 .6 43,P<0 .0 5 ) ;线粒体半定量分析表现出与MDA生成相应的变化。 结论 外源性 CP对心肌缺血再灌注损伤有较好的保护作用 ,其机制可能与其对线粒体结构和氧化磷酸化功能的保护以及核苷酸池的保存、减少氧自由基的产生有关。

Objective\ To study the mechanism of myocardial protection of exogenous creatine phosphate (CP) against ischemia reperfused injury in modified isolated perfused working rat heart model.\ Methods\ Seventy two rats were divided into five groups.The rat hearts of five groups undergone Langendorff perfused were arrested and made totally ischemic for 40 minutes at 37℃ and reperfused for 20 minutes. St.Thomas cardioplegic solution wasn't used in group A;It was used immediately after ischemia in group B and group C,and after 15 minutes ischemia in group D and group E;Group C and group E received the same cardioplegic solution plus creatine phosphate (10mmol/L). The left ventricular work, coronary flow,myocardial adenosine triphosphate(ATP) and malondialdehyde (MDA) content,nicotinamide adenine dinucleotide hydrogen (NADH) level,semiquantitative analysis of mitochondria and ultrastructure were observed.\ Results\ In group E, the left ventricular work was improve (P<0.05),coronary flow increased (P<0.05) and adenosine triphosphate content was higher as compared with group D(P<0 05) during reperfusion.While there was no differences of all above parameters between group B and group C.Malondialdehyde and nicotinamide adenine dinucleotide hydrogen levels remarkably decreased in group C and group E compared with group B and group D(P<0.05) during reperfusion.No correlation was found between levels of adenosine triphosphate at the end of ischemia and malondialdehyde at 20 minutes after reperfusion in group C and group E.However,there was a negative linear correlation (r=-0.643,P<0.05) in group B and group D.Semiquantitative study of the mitochondria demonstrated parallel changes with malondialdehyde following ischemia.\ Conclusion\ Exogenous creatine phosphate could noticeably strengthen protective effect against prolonged myocardial ischemia and reperfusion injury.Its mechanism might be related directly to the reduction of oxygen free radical by protecting mitochondrial oxidative phosphorylation and the nucleotide pool.