Department of Cardiology, Gifu University Graduate School of Medicine, Gifu, Japan.
Am J Physiol Heart Circ Physiol. 2010 Oct;299(4):H1174-82. doi: 10.1152/ajpheart.00116.2010. Epub 2010 Aug 6.
Granulocyte colony-stimulating factor (G-CSF) has been reported to improve cardiac function after myocardial infarction. However, whether postinfarct acute effect of G-CSF is mediated through the same signaling pathways as those of ischemic postconditioning is still unclear. We examined the postinfarct acute effect of G-CSF on myocardial infarct size and its precise molecular mechanism. Japanese white rabbits underwent 30 min of ischemia and 48 h of reperfusion. Rabbits were intravenously injected 10 μg/kg of G-CSF (G-CSF group) or saline (control group) immediately after reperfusion. The wortmannin + G-CSF, PD-98059 + G-CSF, N(ω)-nitro-L-arginine methyl ester (l-NAME) + G-CSF, and 5-hydroxydecanoic acid sodium salt (5-HD) + G-CSF groups were respectively injected with wortmannin (0.6 mg/kg), PD-98059 (0.3 mg/kg), L-NAME (10 mg/kg), and 5-HD (5 mg/kg) 5 min before G-CSF administration. Myocardial infarct size was calculated as a percentage of the risk area of the left ventricle. Western blot analysis was performed to examine the signals such as protein kinase B (Akt), extracellular signal-regulated protein kinase (ERK), eNOS, p70S6 kinase (p70S6K), and glycogen synthase kinase-3β (GSK3β) in the ischemic myocardium after 48 h of reperfusion. The infarct size was significantly smaller in the G-CSF group (26.7 ± 2.7%) than in the control group (42.3 ± 4.6%). The infarct size-reducing effect of G-CSF was completely blocked by wortmannin (44.7 ± 4.8%), PD-98059 (38.3 ± 3.9%), L-NAME (42.1 ± 4.2%), and 5-HD (42.5 ± 1.7%). Wortmannin, PD-98059, L-NAME, or 5-HD alone did not affect the infarct size. Western blotting showed higher myocardial expression of phospho-Akt, phospho-ERK, phosho-eNOS, phosho-p70S6K, and phosho-GSK3β at 10 min and 48 h after reperfusion in the G-CSF group than in the control group. In conclusion, postreperfusion G-CSF administration reduces myocardial infarct size via activation of phosphatidylinositol 3-kinase-Akt and ERK prosurvival signaling pathways and their downstream targets eNOS, p70S6 kinase, GSK3β, and mitochondrial ATP-dependent K(+) channel.
粒细胞集落刺激因子（G-CSF）已被报道可改善心肌梗死后的心脏功能。然而，G-CSF 对梗死后的急性作用是否通过与缺血后处理相同的信号通路介导尚不清楚。我们研究了 G-CSF 对心肌梗死面积的梗死后急性作用及其确切的分子机制。日本白兔进行 30 分钟缺血和 48 小时再灌注。再灌注后立即给予 G-CSF（G-CSF 组）或生理盐水（对照组）静脉注射 10μg/kg。Wortmannin+G-CSF、PD-98059+G-CSF、N（ω）-硝基-L-精氨酸甲酯（L-NAME）+G-CSF 和 5-羟基癸酸钠盐（5-HD）+G-CSF 组分别在 G-CSF 给药前 5 分钟注射 Wortmannin（0.6mg/kg）、PD-98059（0.3mg/kg）、L-NAME（10mg/kg）和 5-HD（5mg/kg）。通过 Western blot 分析检测缺血心肌再灌注 48 小时后的蛋白激酶 B（Akt）、细胞外信号调节蛋白激酶（ERK）、内皮型一氧化氮合酶（eNOS）、p70S6 激酶（p70S6K）和糖原合成酶激酶-3β（GSK3β）等信号。G-CSF 组的梗死面积明显小于对照组（26.7±2.7%比 42.3±4.6%）。Wortmannin（44.7±4.8%）、PD-98059（38.3±3.9%）、L-NAME（42.1±4.2%）和 5-HD（42.5±1.7%）完全阻断了 G-CSF 的梗死面积减少作用。Wortmannin、PD-98059、L-NAME 或 5-HD 单独不影响梗死面积。Western blot 显示 G-CSF 组再灌注后 10 分钟和 48 小时心肌磷酸化 Akt、磷酸化 ERK、磷酸化 eNOS、磷酸化 p70S6K 和磷酸化 GSK3β的表达均高于对照组。结论：再灌注后 G-CSF 给药通过激活磷脂酰肌醇 3-激酶-Akt 和 ERK 生存信号通路及其下游靶标 eNOS、p70S6 激酶、GSK3β 和线粒体 ATP 依赖性 K（+）通道减少心肌梗死面积。
