环磷酸腺苷信号通路在二氮嗪预处理中对离体鼠心肌的保护作用  

The Role of Cyclic Adenosine Monophosphate Signaling Pathway in Myocardial Protection by Diazoxide Preconditioning:Experiment with Isolated Rat Hearts

作　　者：韩劲松[1] 王辉山[1] 韩宏光[1] 汪曾炜[1] 阎德民[1] 李新民[1] 尹宗涛[1] 

机构地区：[1]沈阳军区总医院心血管外科,沈阳110016

出　　处：《中国胸心血管外科临床杂志》2010年第5期390-394,共5页Chinese Journal of Clinical Thoracic and Cardiovascular Surgery

摘　　要：目的研究离体大鼠心肌经二氮嗪预处理(DPC)后环磷酸腺苷(cAMP)及环磷酸腺苷依赖蛋白激酶(PKA)表达的变化,探讨cAMP信号通路在DPC心肌保护作用中可能的机制。方法将40只Wistar大鼠建立离体心脏Langendorff灌注模型,随机分成4组,缺血再灌注组(I/R组,n=10):在心脏平衡灌流30 min后,缺血30 min再灌注K-H液1 h;二氮嗪预处理组(DPC组,n=10):在心脏平衡灌流10 min后,给予含二氮嗪(100μmol/L)的K-H液灌注5 min,再复灌不含二氮嗪的K-H液5 min后,再给予含二氮嗪的K-H液灌注5 min,再复灌不含二氮嗪的K-H液5 min,然后缺血30 min,再灌注K-H液60 min;空白对照组(对照组,n=10):用等量盐水代替二氮嗪,过程同DPC组;二甲基亚砜组(DMSO组,n=10):用DMSO代替二氮嗪,过程同DPC组。取缺氧前和复灌30 min后的冠脉流出液,测定肌酸激酶(CK)的活性,心肌丙二醛(MDA)和超氧化物歧化酶(SOD)含量,比较各组心肌梗死范围、心肌组织cAMP和环磷酸腺苷PKA含量的变化。结果心肌组织中MDA含量DPC组较I/R组明显减少(8.28±2.04 nmol/mg vs.15.52±2.18 nmol/mg,q=11.761,P<0.05),SOD含量明显增加(621.39±86.23 U/mg vs.477.48±65.20 U/mg,q=5.598,P<0.05);复灌30 min后DPC组冠脉流出液CK活性较I/R组明显减少(82.55±10.08 U/L vs.101.64±19.24 U/L,q=5.598,P<0.05);心肌梗死面积明显减少(5.63%±9.23%vs.17.58%±5.76%,q=6.176,P<0.05)。心肌组织cAMP含量DPC组较I/R组明显增加(0.64±0.07 pmol/g vs.0.34±0.05pmol/g,q=14.738,P<0.05);PKA含量DPC组较I/R组明显增加[17.13±1.57 pmol/(L.min.mg)vs.12.85±2.01 pmol/(L.min.mg),P<0.05]。I/R组与DMSO组、对照组上述指标比较均差异无统计学意义(P>0.05)。结论 DPC能增加心肌组织中cAMP、PKA的产生和释放,拮抗氧自由基,减轻心肌I/R损伤,cAMP信号通路可能参与DPC保护机制的触发过程。Objective To study the changes of the cyclic adenosine monophosphate（cAMP） and protein kinase A（PKA） expression of isolated rat hearts after diazoxide preconditioning（DPC）,and to explore the possible mechanism of cAMP signaling pathway in myocardial protection by DPC. Methods Isolated working heart Langendorff perfusion models of 40 Wistar rats were set up and were divided randomly into four groups.For the ischemia reperfusion injury（I/R） group（n=10）,30 min of equilibrium perfusion was followed by a 60 min reperfusion of Krebs-Henseleit（K-H） fluid.The DPC group（n=10） had a 10 min equilibrium perfusion and two cycles of 5 min of 100 μmol/L diazoxide perfusion followed by a 5 min diazoxide-free period before the 30 min ischemia and the 60 min reperfusion of K-H fluid.The blank control group（control group,n=10） and the Dimethyl Sulphoxide（DMSO） group（n=10） were perfused with the same treatment as in the DPC group except that diazoxide was replaced by natriichloridum and DMSO respectively.The activity of creatine kinase（CK） in coronary outflow,the activity of malonyldialdehyde（MDA） and superoxide dismutase（SOD） in myocardium were detected.And the scope of myocardial infarction and the concentrations of myocardial cAMP and PKA were also assessed. Results Compared with the I/R group,the level of MDA for the DPC group decreased significantly（8.28±2.04 nmol/mg vs.15.52±2.18 nmol/mg,q=11.761,P〈0.05）,the level of SOD increased significantly（621.39±86.23 U/mg vs.477.48± 65.20 U/mg,q=5.598,P〈0.05）.After a 30 min reperfusion,compared with the I/R group,the content of CK decreased significantly（82.55±10.08 U/L vs.101.64±19.24 U/L,q=5.598,P〈0.05） and the infarct size reduced significantly（5.63%±9.23% vs.17.58%±5.76%,q=6.176,P〈0.05） in the DPC group.The cAMP concentration in the DPC group was much higher than that in the I/R group（0.64±0.07 pmol/g vs.0.34±0.05 pmol/g,q=14.738,P〈0.05）,and PKA concentration was also much higher than that i

关 键 词：预处理 二氮嗪 环磷酸腺苷 环磷酸腺苷依赖蛋白激酶 线粒体 

分 类 号：R654.1[医药卫生—外科学]