异丙肾上腺素致大鼠心脏肥大时的心肌线粒体钙转运变化

ALTERATIONS OF Ca^(2+) TRANSPORT IN MITOCHONDRIA ISOLATED FROM ISOPROTERENOL INDUCED HYPERTROPHIC MYOCARDIUM

目的：在异丙肾上腺素（Iso）导致的心肌肥大纤维化模型上观察了心肌线粒体钙转运功能的变化。方法：大鼠经皮下注射Iso共10天以制备心肌纤维化模型，心肌线粒体以差速离心法分离。结果：心脏重量／体重比值增加40％（P＜0．01），心肌胶原含量增加81％（P＜0．01），心脏组织呈显著的肥大和纤维化表现。心肌线粒体时间依赖和钙浓度依赖的钙摄取显著低于对照组，其摄取的Vmax较对照组低50％（P＜0．01），但Km值无显著差别。Vmax与心脏重量／体重比值呈负相关（r=－0.67，P＜0．01）。结论：上述结果提示Iso心肌损伤时，线粒体钙转运能力的降低可能与心肌肥大纤维化的发生具有密切的关系。

Objective:45Ca2+ transport of cardiac mitochondria was investigated on the model of isoproterenol induced cardiac hypertrophy. Methods: Rats were received injections of isoproterenol subcutaneously. Results:The ratio of heart weight to body weight increased by 40 % (P < 0. 01 ), presented typical cardiac hypertrophy and interstitial cell fibrosis. Significant changes in mitochondrial 45Ca2+ transport were observed. 45Ca2+ uptake of myocardial mitochondia was lower than that of control. Vmax of calcium uptake decreased by 50% compared with that of contro(P < 0. 01 ), but K. remained unchanged. Conclusion: The results suggest that changes in metabolism of cardiac tissue and transport of cardiac mitochondria may play important roes in the development of cardiac hypertrophy.