【摘要】 目的　探讨心肌衰老机制。　方法　采用 Wistar大鼠 ,分老龄组 (2 2月龄 )和成年组 (7月龄 )。用透射电镜观察心肌细胞器形态定性改变 ;用体视学方法测定心肌细胞器形态定量改变 ;用 X射线能谱仪分析心肌细胞器调控 Ca2 +能力。　结果　与成年组比较 ,老龄组大鼠心肌改变 :(1)核有切痕、肌原纤维不规整、闰盘离解、线粒体和肌浆网肿胀、脂褐素和残余体增多。(2 )在心肌组织内 ,非肌细胞所占体积份数增加 ,线粒体和肌浆网体密度减少 ,线粒体外膜比面积、内膜 +嵴比面积、肌浆网比面积减少。(3)在舒张状态下 ,肌原纤维和线粒体内 Ca2 +增加 ,肌浆网内 Ca2 +减少。　结论　衰老心肌的舒缩力减退 ,心肌细胞器形态呈明显改变 ,心肌衰老与线粒体和肌浆网的形态改变及其调控 Ca2 +能力有直接关系。更多还原

【Abstract】 Objective To study the mechanism of myocardical aging. Methods Wistar rats used were divided aging group (22 months old) and adult group (7 months old). Qualitative morphological changes of organelles of myocardium were observed by TEM. Quantitative morphological changes of organelles of myocardium were determined by stereological method, Ca 2+ regulation of organelles of myocardium were analysed by EDS. Results Compared with adult group, aging group:(1) The nuclei were indented, myofibril were arranged irregularly, intercalated disk were separated, mitochondria and sarcoplasmic reticulum were swelled, lipofuscin and residual body were increased. (2) The volume of myocardium not occupied by myocyte were increased, the volume density of mitochondria and sarcoplasmic reticulum were reduced, specific surface of outer membrance of mitochondria inter membrane plus cristae of mitochondria and the membrane of sarcoplasmic reticulum were also reduced. (3) Ca 2+ in myofibril and mitochondria were increased, but Ca 2+ in sarcoplasmic reticulum were decreased. Conclusion The contractility of aging myocardium were declined, the morphological changes and Ca 2+ regulation of mitochondria and sarcoplasmic reticulum might be directly related to myocardical aging.更多还原