G-CSF预处理对家兔心肌缺血/再灌注损伤的影响

Effect of granulocyte colony-stimulating factor preconditioning on myocardial ischemia/reperfusion injury in rabbits

目的探讨粒细胞集落刺激因子(G-CSF)预处理对心肌缺血/再灌注损伤的影响机制。方法25只健康家兔,随机分为3组:假手术对照组(Sham组,n=8),生理盐水组(NS组,n=9),G-CSF组(n=8)。Sham组开胸后心肌动脉只穿线不结扎;G-CSF组于术前连续5天皮下注射G-CSF 10μg.kg-1.d-11;NS组皮下注射生理盐水0.5 m l每日1次,连续5天;使用开胸法建立缺血/再灌注动物模型,光镜下观察各实验形态学改变,计数缺血区周边部毛细血管数量,免疫组化观察各组Bax、Bc l-2凋亡相关蛋白的表达,比较各组心肌细胞凋亡的程度。模型制备成功后,M acLab生理记录仪测定再灌注后左心室发展压(LVDP)及左心室内压最大上升和下降速率(+dp/dtm ax),比较各组间心功能差异。结果G-CSF组及NS组心功能均较Sham组下降(P(0.01),但G-CSF组心功能优于NS组(P(0.01)。G-CSF组缺血区周边部毛细血管计数高于NS组及Sham组(P(0.01)。G-CSF组Bc l-2明显高于NS组(P(0.01),Bax则明显低于NS组(P<0.01)。结论①G-CSF可以改善缺血/再灌注家兔的心功能;②G-CSF能够上调抗凋亡蛋白Bcl-2表达,同时抑制了促凋亡蛋白Bax的表达,减少了缺血急性期心肌细胞的凋亡;③G-CSF能够改善缺血心肌细胞的微循环,增加缺血区周边部毛细血管密度。

Objective To investigate the mechanism of granulocyte colony- stimulating factor （G- CSF） preconditioning on myocardial ischemia/reperfusion （I/R） injury. Methods 25 healthy rabbits were randomly divided into three groups： （ 1 ） sham operation group （ Sham group, n = 8 ） ; opening the chest, with only threading under cardiac artery and without ligation. （2） NS group （ n = 9）, subcutaneous injection of 0.5 ml normal saline for 5 days before I/R; （3） G - CSF group （n=8） ： subcu .tgneous injection of G-CSF （10μg · kg^-1· d^-1 for5 days before I/R）. After the animal model of I/R was established for observation of morphological changes and the capillary count with light microscopy and the expression of apoptosis - related proteins Bax and Bcl - 2 -with immunohistochcmistry to compare the myocyte apoptosis in each group. After the animal model was prepared, the post - reperfusion LVDP and ＋ dp/dtmax were determined by MacLab physiological recorder to compare the cardiac functional differences between each group. Results （ 1 ） Cardiac function in both NS group and G - CSF group was lower than that in Sham group （ P 〈 0.01 ）, but was higher than in NS group （ P 〈 0.01 ）. （2） The capillary count was higher in all the treatment groups with G - CSF than in NS group and the Sham group （P 〈 0. 01 ）. （3） In the G - CSF group the expression of Bcl - 2 protein was higher than that in the NS group and the Sham group（ P 〈 0.01 ）, whereas the expression of Bax was markedly lower in G- CSF group than in the NS group（P 〈 0.01 ）. Conclusion （ 1 ） G - CSF could enhance cardiac function of rabbit after I/R injury. （2） G - CSF could upregulate the expression of the anti - apoptesis protein Bcl - 2 and meanwhile restrain the expression of pro - apeptosis protein Bax, and decrease the myocyte apoptosis of acute ischemia, the extent of myocardial apoptesis in ischemia and reperfusion injury. （3） G - CSF could improve the microcireulation of ischemic myocytes and increase the density of peripheral capillaries in ischemic areas.