摘要
目的:探讨应激活化蛋白激酶(JNK MAPK)在大鼠缺血后适应中的变化,并进一步分析其对细胞凋亡的影响。方法:60只SD大鼠随机分为假手术(Sham)、缺血再灌注(R/I)、后适应(Post)、JNK抑制剂(I JNK)、JNK激活剂+后适应(Ani+Post)和JNK激活剂(Ani)6组,建立急性心肌梗死再灌注和缺血后适应模型,在再灌注开始前5min经颈静脉注射抑制剂(SP600125,6mg/kg)和激动剂(anisomycin,2mg/kg)。再灌注6h后处死取心肌组织测定磷酸化JNK(P-JNK)、TNFα、Caspase-8、Bcl-2、Bax,并提取胞浆测定其中细胞色素c(Cyt-c);各组其余大鼠再灌注24h后测定血流动力学,抽血测定心肌酶,取心脏进行TUNEL凋亡检测或使用伊文氏蓝-三苯基氯化四氮唑法检测心肌梗死面积。结果:后适应组可显著改善缺血对左室压力最大上升/下降速度、心率血压积的抑制,限制心肌梗死面积,减轻细胞凋亡和坏死,抑制了P-JNK的生成(1.12±0.21 vs 1.90±0.32,P<0.05);同时,伴随TNFα和Caspase-8表达显著减少,Bcl-2的升高和Bax的降低,胞浆Cyt-c(0.33±0.04 vs 1.00±0.11,P<0.05)含量明显减少。I JNK组可以模拟后适应在信号分子的上述变化,从而表现出显著的心肌保护作用[凋亡指数:(6.23±2.43)%vs(18.22±5.10)%,P<0.05;心肌梗死面积:(23.44±6.34)%vs(42.31±8.21)%,P<0.05]。反之,Ani+Post则因为JNK激活剂的应用,部分抵消了后适应的保护效应,在心肌酶、心肌凋亡和梗死面积方面表现出保护作用的减弱[凋亡:(14.12±2.00)%vs(18.22±5.10)%,P>0.05;心肌梗死面积:(35.27±5.28)%vs(42.31±8.21)%,P>0.05]。结论:后适应可以抑制JNK MAPK在再灌注损伤中的磷酸化,并通过P-JNK MAPK的减少抑制TNFα细胞受体途径和Bcl-2/Bax线粒体途径,从而减少细胞凋亡。
Objective： To test whether postconditioning could inhibit the expression of phospho-JNK （P JNK） mitogen activated protein kinase （MAPK） and study its relation to apoptosis of cardiocyte. Methods： Sixty rats were randomly divided into six groups：sham, reperfusion injury （R/I）, postconditioning （Post）, SP600125 （I _ JNK）, anisomycin and postconditioning （Ani ＋ Post） and anisomycin （Ani） groups. After acute myocardial infarction was induced in rats,placebo solution （DMSO）,SP600125 （6 mg/kg） or anisomyein （2 mg/kg） was injected through jugular vein 5 rain before reperfusion; 6 h later 3 rats of each group were executed and the hearts were separated to measure the signaling molecules （phospho-JNK, TNFα, Caspase 8, Bcl-2/Bax, cytochrome-c）. Twenty-two hours later hemodynamic data were measured in the left rats, and then blood samples were taken to determine serum markers of cardiac damage, and hearts were separated to measure the infarction area and eardiocyte apoptosis. Results： Postconditioning improved ± DP/DTmax of left ventricle, limited infarct area ,relieved apoptosis and necrosis of cardiocytes ,and inhibited the expression of P-JNK（1.12±0.21 vs 1.90±0.32,P〈0.05）. At the same time the levels of TNFα,Caspase 8,Bax and Cyt-c were lower in Post group than those in R/I group,but Bcl-2 expression levels were higher. I _JNK group presented the similar protection effect of postconditioning [TUNEL index： （6.23 ± 2.43） vs （18.22±5.10）%,P〈0.05 ;Infarct area： （23.44±6.34）% vs （42.31±8.21）% ,P〈0.05]. On the other hand,Ani＋Post group partially lost eardioproteetion effect [TUNEL index：（14.12±2.00）% vs （18.22±5.10）%,P〉0.05;Infarct area： （35.27±5.28）% vs （42.31±8.21）%,P〉 0.05], because of the activation of JNK MAPK, Conclusion： Postconditioning can inhibit phosphorylation of JNK MAPK, which attenuates cardiocyte apoptosis by both extrinsic and mitochondria pathway.
出处
《浙江大学学报（医学版）》
CAS
CSCD
北大核心
2009年第6期611-619,共9页
Journal of Zhejiang University(Medical Sciences)
基金
国家自然科学基金资助项目(30740080)
