心脏型脂肪酸结合蛋白在急性缺血心肌中的表达

The expression of heart-type fatty acid-binding protein in the acute ischemic myocardium

目的:观察急性缺血心肌心脏型脂肪酸结合蛋白(H-FABP)基因及蛋白表达的动态变化,揭示H-FABP在心肌代谢异常中的作用。方法:健康SD雄性大鼠随机分为Sham组和5个实验组(A1、A2、A3、A4和A5分别为心肌缺血1、2、4、6和12h);应用HE染色观察各实验组心肌缺血后病理形态学改变,用RT-PCR和WesternBlot的方法检测心肌H-FABP基因和蛋白表达的变化。结果:A2、A3组心肌细胞明显肿胀,有部分形成了"收缩带";A4和A5组心肌细胞边界不清,局灶性凝集坏死,A5组有大量炎性细胞浸润。RT-PCR结果显示A2、A3、A4、A5组与Sham组比较心肌H-FABP基因表达明显下降(P<0.05),尤其A3、A4组降低分别约29%、30%(P<0.01)。WesternBlot检测示A2、A3、A4、A5组与Sham组比较心肌H-FABP蛋白表达均下降,尤其A4组降低约41%(P<0.01)。结论:急性心肌缺血后H-FABP基因及蛋白表达明显下降,可能参与心肌细胞代谢紊乱,是导致局部心肌损伤的机制之一。

Objective To explore the role of heart-type fatty acid binding protein （H-FABP） via observing the changes of mRNA and protein expressions of H-FABP in the ischemie myocardium. Methods 60 Sprague-Dawley male rats were randomized to sham-operated group and five other experimental groups （groups Al to A5 and the blood supply to the myoeardium of the rats in each group was blocked for 1,2,4,6 and 12 h, respectively）. The morphological changes of the ischemic myocardium were examined with HE staining. H-FABP mRNA expressions in the ischemic myocardial tissues were determined by RT-PCR, so were H-FABP protein expressions by Western Blot. Results The myocardial cells were obviously swelling and a ＂shrinking band＂ formed 2 h and 4 h after isehemia; a vague boundary of the cells presented and a focal necrotic lesion occurred 6 h following ischemia; and a lot of inflammatory cells were infiltrated 12 h after ischemia. As compared to the sham-operated group, H-FABP mRNA expressions were significantly decreased in the groups A2 to A5 （P 〈 0.05）, especially in groups A3 and A4 （P 〈 0.01 ）; so were H-FABP protein expression （P 〈 0.05）, particularly in group A4 （P 〈 0.01 ）. Conclusion The significant downregulation of H-FABP after myocardial ischemia may be involved in the imbalance of myocardial metabolism, resulting in local myocardial injury.