组织多普勒超声评价阿霉素诱导兔心肌病早期收缩功能改变的实验研究

目的利用组织多普勒超声心动图评价阿霉素所致兔心肌病心肌功能的连续变化情况.方法 28只日本白兔分为两组,阿霉素组20只,每周静脉注射阿霉素2 mg/kg,8周共计16 mg/kg以期形成心肌病模型.对照组8只,每周注射相同剂量的生理盐水.分别在第0,4,6,8,10,12周进行常规和组织多普勒超声心动图检查.第12周阿霉素组和对照组各取2只处死进行组织学检查.结果阿霉素组,在10、12周左室内径显著扩大,左室射血分数和短轴缩短率显著下降(P<0.05).显著变化最早发现在第10周.二尖瓣环处心肌组织收缩峰值速度在8、10、12周显著降低(P<0.05).显著变化最早发现在第8周.病理结果显示了与人类阿霉素心肌毒性相似的改变,心肌细胞变性、线粒体和肌浆网水肿、细胞内空泡增多.对照组组织学无改变,常规和组织多普勒超声指标均未发现显著变化(P>0.05).结论在阿霉素所致兔心肌病模型中心肌收缩功能降低.组织多普勒指标能早期发现这一变化,早于常规超声心动图指标,为评价左室功能提供了一个敏感的新手段.

Tissue Doppler echocardiographic evaluation of early myocardial contraction abnormality in rabbits with adriamycin-induced cardiomyopathy

Objective To investigate the use of tissue Doppler echocardiography (TDE) in evaluating the temporal changes of left ventricular (LV) myocardial function in rabbits with adriamycin-induced cardiomyopathy. Methods Twenty-eight Japanese rabbits were divided into two groups. Adriamycin was intravenously administered at a dose of 2 mg/kg once a week for 8 weeks (total dose 16 mg/kg) in 20 rabbits to induce the cardiomyopathy model. 8 rabbits served as controls receiving the same amount of saline once a week for a total of 8 weeks. Conventional and tissue Doppler echocardiography were performed at baseline, 4th, 6th week, 8th week, 10th week and 12th week. 2 rabbits from each group were sacrificed for histological study in the 12th week. Results In adriamycin-treated group, LV chamber diameter significantly increased, while (ejection) fraction and fraction shortening decreased significantly in 10th and 12th week (P<0.05). The significant changes were firstly found in 10th week. Mitral annulus systolic velocity by TDE decreased significantly in 8th, 10th and 12th week (P<0.05). The significant changes were firstly found in 8th week. The significant change with characteristics of adriamycin cardiotoxicity in human patients such as cardiomyocytes degeneration, mitochondrial and sacroplasmic reticular edema, numerous intracellular vacuoles were found in the adriamycin-treated group in histological study. In control group, no significant changes were found in histological study and all parameter by tissue Doppler, conventional echocardiography (P>(0.05)). Conclusion Myocardial contraction function was reduced in adriamycin-induced rabbit model of dilated cardiomyopathy. The parameters by tissue Doppler echocardiography detected myocardial contraction abnormality earlier than those by conventional echocardiography in adriamycin-induced cardiomyopathy rabbits, which provide a new sensitive method to evaluate LV function.