摘要
目的观察脑利钠肽(BNP)激活环鸟苷酸/蛋白激酶G(cGMP/PKG)信号通路对线粒体通透性转换孔(mPTP)开放和糖原合成激酶-3β(GSK-3β)磷酸化的影响。方法将48只新西兰兔随机分为4组(12只):假手术组;对照组;BNP组;BNP+KT5823组(KT5823为蛋白激酶G抑制剂)。除了假手术组,其余3组均于结扎左回旋支45 min后恢复左回旋支血流,进行再灌注180 min。全程观察血流动力学及心电变化;实验终末,各组随机抽取6只兔子,采用伊文思蓝和氯化三苯基四氮唑双染色法测定左心室心肌梗死面积;每组另外6只兔子心脏取梗死边缘区组织,用TUNEL法检测缺血再灌注心肌细胞的凋亡,Western blotting方法测定P-GSK-3β/GSK-3β、细胞质细胞色素C/线粒体细胞色素C的表达。结果各组之间HR、MABP差异无统计学意义(均为P>0.05);与对照组相比,BNP组心律失常发生率明显减少(8.3%比83.3%,P<0.0125)。与BNP组比较,BNP+KT5823组心律失常明显增加(75.0%比8.3%,P<0.0125);假手术组无心肌梗死。与对照组比较,BNP组心肌梗死范围明显减少(26.02%±2.17%比40.99%±1.23%,P<0.05)。与BNP组比较,BNP+KT5823组梗死面积明显增加(38.94%±2.04%比26.02%±2.17%,P<0.05);与对照组比较,BNP组GSK-3β的磷酸化水平显著增加(0.7800±0.0506比0.3610±0.0570,P<0.05),细胞质细胞色素C/线粒体细胞色素C明显减少(0.3420±0.0921比0.9530±0.2054,P<0.05)。与BNP组相比,BNP+KT5823组GSK-3β的磷酸化水平明显降低(0.4037±0.0437比0.7800±0.0506,P<0.05),细胞质细胞色素C/线粒体细胞色素C显著增加(0.8037±0.1001比0.3420±0.0921,P<0.05)。与对照组比较,BNP组心肌细胞凋亡数明显减少(4.6%±2.0%比13.1%±2.7%,P<0.05),与BNP组相比,BNP+KT5823组心肌细胞凋亡数显著增加(12.8%±2.3%比4.6%±2.0%,P<0.05)。结论 BNP激活cGMP/PKG信号通路所产生的心肌保护作用与抑制mPTP的开放有关,cGMP/PKG信号通路的激活可以促进GSK-3β磷酸化。
Objective To observe the impact of brain natriuretic peptide （BNP） activated cyclic guanosine monophosphate/protein kinase G （cGMP/PKG） signaling pathway on open of mitoehondrialpermeability transition pore （mPTP） and phosphoiclation of glycogen synthase kinase-3β （GSK-3β）. Methods Totally 48 New Zealand white rabbits were randomly divided into four groups （12 in each group） ： sham group, control group, BNP group and BNP ＋ KT5823 group （ KT5823 is protein kinase G inhibitor）. Occlusion of left circumflex artery for 45 min followed by 180 min reperfusion was performed on rabbits in all groups except those in sham group. Rabbits in sham group underwent open thoracotomy without ligating the left circumflex artery. Hemodynamies and ECG were obtained. At the end of experiment, 6 rabbit hearts were stained by Evan＇s blue/triphenyhetrazolium chloride methods to test the area of infarction. The apoptosis of myocardial cell was determined by terminal deoxynucleotidyl transferase mediated dUTP- biotin nick end-labeling （TUNEL）method. Expression of P-GSK-313/GSK-3β and cytoplasmic cytoehrome C/mitochondrial eytochrome C proteins in the rest hearts were analyzed using western blot assay. Results There was no significant difference in HR and MABP among four groups during I/R period （ P 〉 0.05 ）. Rate of arrhythmia was significantly reduced in BNP group than in control group （8.3% vs. 83.3% , P 〈 0. 0125 ）. Rate of arrhythmia was significantly increased in BNP ＋ KT5823group than in BNP group（75.0% vs. 8.3% ,P 〈 0. 0125 ）. Myocardial infarction did not occur in sham group. Myocardial infarct size was significantly smaller in BNP group than in control group （ 26.02% ± 2. 17% vs. 40. 99% ± 1.23%, P 〈 0. 05）, and was significantly increased in BNP ＋ KT5823 group than in BNP group（38.94% ± 2.04% vs. 26.02% ±2. 17% ,P 〈0. 05 ）. Level of GSK-313 phosphorylation was increased significantly and cytoplasm cytochrome C/mitochondrial cytoehrome C reduced significan
出处
《中国心血管杂志》
2014年第2期134-138,共5页
Chinese Journal of Cardiovascular Medicine
基金
泉州市科技计划项目(2011Z56)~~
关键词
心肌缺血再灌注损伤
细胞凋亡
环鸟苷酸
蛋白激酶G信号通路
线粒体通
透性转换孔
糖原合成激酶-3β
Myocardial ischemia-reperfusion injury
Apoptosis
Cyclic guanosinemonophosphate/protein kinase G signaling pathway
Mitochondrial permeability transition pore
Glycogen synthase kinase-3β
