粒细胞集落刺激因子通过PI3K-Akt通路抑制缺血再灌注损伤

目的:研究经冠状动脉(冠脉)内注入粒细胞集落刺激因子(G-CSF)对大鼠心肌缺血再灌注损伤的预防作用,及其与PI3K-Akt信号转导途径的关系。方法:制备大鼠心肌缺血再灌注模型。再灌注同时经冠脉内给予G-CSF或G-CSF+PI3K激酶抑制剂(LY294002),灌注120min后应用TUNEL法检测细胞凋亡,免疫组织化学法观察凋亡相关蛋白Bax及Bcl-2及caspase-3表达情况,免疫印迹检测总-Akt(t-Akt)及磷酸化Akt(p-Akt)表达。结果:缺血再灌注同时给予冠脉内G-CSF治疗能够显著减轻缺血区心肌细胞凋亡,降低Bax、caspase-3的表达,增高心肌细胞内Bcl-2表达,同时p-Akt的蛋白水平显著增高(P<0.01)。LY294002阻断Akt活化后,抑制了G-CSF诱导的抗心肌细胞凋亡作用。结论:缺血再灌注同时冠脉内给予G-CSF可保护梗死区残存的心肌细胞,减少缺血再灌注所诱导的心肌细胞凋亡,其保护机制与PI3K-Akt信号通路有关。

Granulocyte colony-stimulating factor inhibits ischemia-reperfusion injury via PI3K/Akt signal pathway

Objective:To study whether direct intracoronary granulocyte colony-stimulating factor(G-CSF) injection at the onset of reperfusion could attenuate myocardial ischemia-reperfusion injury(I/R) in the acute phase.To evaluated whether the G-CSF could activate phosphatidylinositol-3 kinase(PI3K),which is the signal transducer and activator of Akt in cardiomyocytes. Method:Male rat ischemia-reperfusion model was prepared and G-CSF was injected into the coronary artery immediately after reperfusion.LY294002,a PI3K inhibitor,was selectively injected into the LAD after the G-CSF injection.Apoptosis of cardiomyocytes was assessed using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay(TUNEL assay).Immunohistochemistry was used to detect the lavels of Bax,Bcl-2 and caspase 3.Western blotting was used to analyze the level of total Akt and phosphorylated Akt in all the groups. Result:G-CSF significantly(P<0.01) reduced myocardial apoptosis index(AI) (55.8±4.2)%∶(28.2±3.3)%] compared with the I/R group.G-CSF treatment attenuated the level of Bax and increased the level of Bcl-2 and p-Akt in the ischemic myocardium.LY294002 blunted the beneficial effects of G-CSF. Conclusion:The G-CSF attenuating myocardial ischemia reperfusion injury seems to be associated with its antiapoptotic action mediated by upregulation of p-Akt signal way.