缺氧性肺动脉高压大鼠心肌超微结构的观察

Ultrastructural Changes of Myocardium in Rats with Hypoxic Pulmonary Hypertension

本文观察模拟5000m高度低压舱内慢性缺氧大鼠心肌超微结构的变化.取材前对大鼠作心功能检查,取左、右心室心肌做常规电镜标本。结果表明,缺氧40d大鼠右心室心肌肌原纤维形态虽属基本正常.偶见Z线模糊或Z线消失,线粒体数量稍有增加,排列紊乱,线粒体的嵴有各种形态的变化。缺氧60d者心肌纤维的变化更为明显,肌微丝受损。这与右室代偿功能明显削弱的表现是一致的。左室心肌肌原纤维与线粒体结构的改变较轻,与左室功能变化幅度较小相一致.以上结果表明慢性缺氧过程中有心功能代偿性增强达到顶点后出现回降是心肌开始发生病理性改变的一种反映。

Ultrastructural changes of the myocardia of rats with chronic hypoxia for 40 and 60 days are reported. The rats were caged in a hypobaric chamber simulating an altitude of 5000 meters above sea level. The heart functions were ex-amined before myocardial specimens were taken from both ventricles for electron microscopy study. The results indicated that the myofibril structure of the right ventricle remained normal in the 40 days hypoxic group, except for the occasional appearance of obscure or disappearing Z lines. The mitochondria were slightly increased in number, with a disarrangement of the mitochondria and structural changes in the cristae. The myofibrils of the 60 days hypoxic group showed more obvious structural changes, with disruption of myofilaments. structural changes in the right ventricle were consistant with apparent decompensation of the right ventricle. The changes of myocardium and mitochondria in the left ventricle were similar to but less severe than those in the right ventricle, and this observation corresponds with a less severe decompensation of the left ventricle. The data suggest that during chronic hypoxic exposure, a decline occurring after the peak increase of cardiac conpensation might signal the onset of structural changes of the myocardium.