心力衰竭大鼠心肌细胞增殖与心功能的关系研究

Relationship between myocyte proliferation a nd cardiac function in adult rats with heart failure

目的证实成年心力衰竭大鼠心肌细胞存在分化增殖,探讨心肌细胞增殖程度与心功能的相关关系。方法成年SD雄性大鼠分为2组:心肌梗死组(14只,其中心功能代偿8只、失代偿6只),正常对照组(8只)。结扎左冠状动脉前降支形成心肌梗死,建立大鼠心力衰竭模型。1个月后,测血流动力学。心肌组织进行碘化丙啶和α-肌原节肌动蛋白抗体免疫荧光染色,观察心肌细胞有丝分裂相。用增殖细胞核抗原(PCNA)抗体进行免疫组化染色,观察PCNA阳性率。结果(1)成年大鼠左室心肌组织可观察到心肌细胞有丝分裂相。(2)心肌梗死后心功能代偿组PCNA阳性率明显高于对照组(7.2%±1.4%vs2.2%±0.8%,P<0.01),与心功能失代偿组比较差异无统计学意义(3.0%±1.3%vs2.2%±0.8%,P=0.648);心功能代偿组显著高于心功能失代偿组(P<0.01)。(3)心肌梗死组PCNA阳性率与±LVdp/dtmax相关系数分别为0.80(P<0.01)和-0.76(P<0.01)。结论(1)成年心力衰竭大鼠心脏存在心肌细胞增殖;(2)心肌梗死大鼠心肌细胞增殖程度与心脏收缩功能呈正性相关,与舒张功能呈负性相关。

Objective To confirm whether there is myocytes proliferation in the adult rat with heart failure or not, and to investigate the relationship between myocyte proliferation and heart function. Methods Descending anterior branch of left coronary artery was ligated in 20 adult male SD rats so as to establish an heart failure models. Eight rats were used as controls. Hemoclynamic parameters, blood pressure （BP） , left ventricle end systolic pressure （ LVESP）, left ventricle end diastolic pressure （ LVEDP）, ＋LVdp/dtmax, and -LVdp/dtmax, were measured 30 days after the coronary occlusion. Based on the results of heart function examination, the heart infarct rats were divided into 2 subgroups： cardiac functional compensation subgroup （8 rats） , and cardiac functional decompensation subgroup （6 rats）. Then the rats were killed and their hearts were taken out and stained with propedium iodide （PI） and antibody to α-sarcomeric actin. Immunohistochehemistry was used to detect the proliferation cell nuclear antigen （PCNA）. Confocal microscopy was used to observe the mitotic image. Light microscopy was used to observe the PCNA positive rate in the myocardium. Results （1） Mitotic images of myocytes could be identified by confocal microscopy in the left ventricle of all rats. （2） PCNA expression was detected in the nuclei of both infarct and normal hearts. The PCNA positive rate of the cardiac functional compensation subgroup was 7. 2%±1.4% , significantly higher than that of the control group （ 2. 2%±0. 8%, P=0. 648 ）. However, the PCNA positive rate of the cardiac functional decompensation subgroup was 3. 0%±1. 3%, not significantly different from that of the control group （ P = 0.648 ）. （ 3 ） The correlation coefficient between PCNA-positivity of cardiomyocytes and ＋ LVdp/dtmax, in the infarct rats were 0.80 （ P 〈 0.01 ） and the correlation coefficient between PCNA-positivity of cardiomyocytes and -LVdp/dtmax was-0.76 （ P=0. 01 ）. Conclusion （1） There is myocyte proliferation in the adult rat heart. （2） Myocyte proliferation is positively correlated with heart systolic function, and negatively correlated with heart diastolic function in chronic heart failure.