Stat5-dependent cardioprotection in late remote ischaemia preconditioning
Stat5-dependent cardioprotection in late remote ischaemia preconditioning
复制标题
晚期远端缺血预适应中 Stat5 依赖性心脏保护作用
DOI：
10.1093/cvr/cvy014
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发表时间：
2018-04-01
影响因子：
10.8
通讯作者：
Zhu, Bing-Mei
中科院分区：
文献类型：
--
作者：
Chen, Hui;Jing, Xin-Yue;Zhu, Bing-Mei
旨在
采用心肌细胞特异性Stat 5基因敲除小鼠（Stat 5-cKO）研究晚期远端缺血预处理（RIPC）对心肌缺血/再灌注（I/R）损伤的保护作用，并探讨Stat 5是否参与了这种保护作用。
方法和结果
将小鼠暴露于下肢RIPC或假缺血。24 h后，结扎左前降支（LAD）30 min，再灌注180 min，检测心肌梗死面积（IS）、心肌细胞凋亡率和血清心肌酶，评价其心肌保护作用。收获心脏组织以确定心肌细胞的抗凋亡和存活信号传导。当与没有RIPC的Stat 5 fl/fl小鼠相比时，具有RIPC的Stat 5 fl/fl小鼠（Stat 5 fl/fl+RIPC + I/R）显示心肌IS/LV降低（16 ± 1.5%对30.1 ± 3.1%，P < 0.01; IS/危险区（AAR），42.2 ± 3.5vs.69.2 ± 4.9%，P < 0.01），心肌细胞凋亡率降低（2.1 ± 0.37vs5.5 ± 0.53%，P < 0.01），肌酸激酶（CK）、乳酸脱氢酶（LDH）和肌酸激酶同工酶（CK-MB）水平降低。相反，Stat 5-cKO小鼠（Stat 5 fl/fl; Tnnt 2Cremice，用强力霉素处理7天）没有表现出任何RIPC诱导的心脏保护作用。Stat 5 fl/fl+RIPC + I/R组的STAT 5蛋白活化显著高于Stat 5 fl/fl+I/R组，而Stat 5-cKO + RIPC + I/R组与Stat 5-cKO + I/R组之间无显著差异。心脏组织的进一步分析检测到Stat 5 fl/fl+RIPC + I/R小鼠中细胞色素c（Cyt c）和裂解的Caspase-3蛋白表达降低，沿着抗凋亡分子增加，包括特大B细胞淋巴瘤（Bcl-xL）和B细胞淋巴瘤-2（Bcl-2）;在Stat 5-cKO + RIPC + I/R小鼠中未观察到此类变化。此外，RIPC增加心脏缺氧诱导因子-1（HIF-1α）和白细胞介素-10（IL-10）蛋白水平，并导致Stat 5 fl/fl小鼠心脏中AKT、磷脂酰肌醇3激酶（PI 3 K）和血管内皮生长因子活化。然而，这些变化被Stat 5的缺乏完全抑制。
结论
这些结果表明，RIPC诱导的晚期心脏保护心肌I/R损伤是Stat 5依赖性的，并与抗凋亡信号和心肌细胞存活信号的激活。
Aims
To study the protective effects of late remote ischaemic preconditioning (RIPC) against myocardial ischaemia/reperfusion (I/R) injury and determine whether Stat5 is involved in this protection by using cardiomyocyte-specific Stat5 knockout mice (Stat5-cKO).
Methods and results
Mice were exposed to lower limb RIPC or sham ischaemia. After 24 h, the left anterior descending artery (LAD) was ligated for 30 min, then reperfused for 180 min. The myocardial infarct size (IS), apoptotic rate of cardiomyocytes, and serum myocardial enzymes were measured to evaluate for cardioprotective effects. Heart tissues were harvested to determine the cardiomyocytes' anti-apoptotic and survival signaling. When compared with the Stat5fl/fl mice without RIPC, Stat5fl/fl mice with RIPC (Stat5fl/fl+RIPC + I/R) displayed a decreased myocardial IS/LV (16 ± 1.5 vs. 30.1 ± 3.1%, P < 0.01; IS/ area at risk (AAR), 42.2 ± 3.5 vs. 69.2 ± 4.9%, P < 0.01), a reduced cardiomyocyte apoptotic rate (2.1 ± 0.37 vs. 5.5 ± 0.53%, P < 0.01), and lower creatine kinase (CK), lactate dehydrogenase (LDH), and creatine kinase-MB (CK-MB) levels. To the contrary, the Stat5-cKO mice (Stat5fl/fl; Tnnt2Cremice with Doxycycline treatment for 7 days) did not exhibit any effect of RIPC-induced cardioprotection. Activation of STAT5 protein was significantly higher in the Stat5fl/fl+RIPC + I/R group than in the Stat5fl/fl+I/R group, while there was no significant difference between the Stat5-cKO + RIPC + I/R and the Stat5-cKO + I/R group. Further analyses with heart tissues detected decreased protein expressions of cytochrome c (Cyt c) and cleaved Caspase-3 in the Stat5fl/fl+RIPC + I/R mice, along with increased anti-apoptotic molecules, including B-cell lymphoma-extra large (Bcl-xL) and B-cell lymphoma-2 (Bcl-2); such changes were not noted in the Stat5-cKO + RIPC + I/R mice. Additionally, RIPC increased cardiac hypoxia inducible factor-1 (HIF-1α) and interleukin-10 (IL10) protein levels and caused activation of AKT, phosphatidylinositol 3 kinase (PI3K), and vascular endothelial growth factor in the heart of the Stat5fl/fl mice. However, these changes were completely inhibited by the absence of Stat5.
Conclusions
These results suggest that RIPC-induced late cardioprotection against myocardial I/R injury is Stat5-dependent and is correlated with the activation of anti-apoptotic signaling and cardiomyocyte-survival signaling.