Quantitative x-ray microanalysis of the elemental composition of individual myocytes in hypoxic rabbit myocardium.
Quantitative x-ray microanalysis of the elemental composition of individual myocytes in hypoxic rabbit myocardium.
复制标题
对缺氧兔心肌中单个心肌细胞的元素组成进行定量 X 射线微量分析。
DOI：
10.1161/01.cir.68.4.872
复制
发表时间：
1983
期刊：
影响因子：
37.8
通讯作者：
Willerson,JT
中科院分区：
文献类型：
--
作者：
Buja,LM;Burton,KP;Hagler,HK;Willerson,JT
本研究的目的是使用能量色散X射线微区分析来检验以下假设：（1）单个心肌细胞在缺氧时细胞内离子稳态改变的严重程度可能表现出重要的变化;（2）缺氧心肌细胞可能积累某些元素，其数量足以损害细胞器的功能和结构。用附有小的右心室乳头肌的兔室间隔制备物来获得对照氧合心肌（6个乳头肌）和缺氧1至1 1/2小时的心肌（n = 8）。还获得了未在体外灌注的心肌细胞（n = 4）。对未固定的乳头肌的冻干薄切片进行微量分析。元素浓度通过感兴趣的元素的合适的冷冻标准来确定。大多数缺氧心肌细胞的肌浆和线粒体表现出显着的变化，包括钠和氯的增加和钾，磷，镁的减少，而钙没有重大变化的扩散元素。最严重改变的心肌细胞表现出钙超载的证据，表现为与形成电子致密的线粒体内含物相关的线粒体钙和磷水平显着增加。线粒体钙和磷的水平超过了以前发现的明显损害分离的线粒体的功能和结构。因此，未固定的冷冻切片的X-射线显微分析提供了损伤心肌中单个肌细胞元素组成的亚细胞改变的直接测量，并证明了钙和磷在严重损伤的肌细胞的线粒体中积累，其浓度足以对这些细胞器产生有害影响。
The purpose of this study was to use energy dispersive x-ray microanalysis to test the following hypotheses: (1) that individual myocytes may exhibit important variation in the severity of alterations in intracellular ionic homeostasis in response to hypoxia and (2) that hypoxic myocytes may accumulate certain elements in quantities sufficient to impair organellar function and structure. A rabbit interventricular septal preparation with attached small right ventricular papillary muscles was used to obtain control oxygenated myocardium (six papillary muscles) and myocardium rendered hypoxic for 1 to 1 1/2 hr (n = 8). Myocardium not perfused in vitro was also obtained (n = 4). Microanalysis was performed on freeze-dried thin sections of unfixed papillary muscles. Elemental concentrations were determined by suitable cryostandards of elements of interest. Sarcoplasm and mitochondria of most hypoxic myocytes exhibited significant alterations of diffusible elements, including increases in sodium and chloride and decreases in potassium, phosphorus, and magnesium, without major change in calcium. The most severely altered myocytes showed evidence of calcium overloading manifested by markedly increased levels of mitochondrial calcium and phosphorus associated with formation of electron-dense mitochondrial inclusions. Levels of mitochondrial calcium and phosphorus exceeded those previously found to markedly impair the function and structure of isolated mitochondria. Thus x-ray microanalysis of unfixed cryosections provides direct measurements of subcellular alterations in elemental composition of individual myocytes in injured myocardium and demonstrates that both calcium and phosphorus accumulate in mitochondria of severely injured myocytes in concentrations sufficient to exert deleterious effects on these organelles.