红细胞生成素对大鼠心肌细胞凋亡相关基因表达的影响(英文)

Erythropoietin protects against myocardial ischemia/reperfusion injury by inhibition of apoptosis and up-regulation of Bcl-2

目的探讨红细胞生成素(erythropoietin,EPO)对大鼠心肌缺血-再灌注损伤(ischemia-reperfu-sioninjury,IRI)时心肌细胞凋亡及Bcl-2、Bax基因及蛋白表达的影响。方法35只大鼠随机分成4组:假手术组(SHAM)、缺血再灌注组(IR)、红细胞生成素干预1组(EPO1)和红细胞生成素干预2组(EPO2)。以左冠脉穿线结扎法制备心肌缺血再灌注模型,造模前24h开始给药。以缺口末端标记法(TUNEL)检测凋亡细胞,S-P免疫组化法检测心肌Bcl-2、Bax蛋白表达,RT-PCR对Bcl-2、Bax的mRNA做半定量分析。结果与IR组相比,EPO干预组的凋亡细胞指数[apoptoticindex,A1,A1(%)=平均光密度×阳性细胞百分比×100]有明显下降。EPO2组的Bcl-2基因及蛋白表达均明显高于IR组[(0.29±0.04)vs(0.10±0.02),P=0,P<0.01;(4.97±1.82)vs(2.12±1.24),P=0.01,P<0.05)];而EPO干预组的Bax基因及蛋白表达与IR组之间并无显著差异。结论EPO干预对大鼠心肌IRI具有显著的抑制细胞凋亡的作用,其机制可能与诱导Bcl-2基因及蛋白表达,提高了Bcl-2/Bax的比值有关。

[Objective] To study the effect of pretreatment of erythropoietin （EPO） on myocardial apoptosis, gene and protein expression of Bcl-2 and Bax in rat myocardium tissue after ischemia/reperfusion injury （IRI）. [Methods] Thirty-five rats were divided randomly into 4 groups, i.e. ischemia-reperfusion group （IR）, sham-operation group （SHAM）, EPO （500 U/kg）-treated group I （EPOI）, and EPO （3 000 U/kg）-treated group 2 （EPO2）. The ischemia-reperfusion heart model was established by ligating the left anterior descending branch of coronary artery. In EPO1 and EPO2 groups, the rats were treated with EPO 24 h before IRI. Myocardial cell apoptosis was estimated by in situ nick end labeling （TUNEL） method; Bcl-2 and Bax mRNA transcript and protein expression were detected by RT-PCR and S-P immunohistochemistry. [Result] Compared with IR group, the myocyte apoptotic indexes [AI（%） = average optical density xopposite cell pereentagexI00] of EPO administration groups were significantly decreased （P 〈0.05）. Compared with IR group, Bcl-2 gene and protein expressions in EPO2 group were significantly increased [（0.29±0.04 ）vs （0.10±0.02）, P 〈0.01; （4.97±1.82）vs（2.12±1.24）, P 〈0.05]. There were no significant changes in Bax gene and protein expressions between IR and EPO treatment groups. [Conclusion] EPO pretreatment prevents rat myocardium ischemia/reperfusion injury by significant inhibition on apoptosis, which might be due to up-regulation of Bcl-2 gene and protein expression, hence raising the ratio of Bcl-2/Bax.