LeFurgey A, Ingram P, Henry S C, Murphy E, Lieberman M
Scan Electron Microsc. 1983(Pt 1):293-303.
The mitochondria of chick heart cells grown in monolayer culture occupy a relatively large percentage (30%) of the cell cytoplasmic volume, as determined by thin section morphometry, and vary in their ultrastructural configuration in response to different functional states of the cell. The present study was undertaken to determine the three-dimensional structure of the mitochondria in cardiac cells, since reconstruction experiments have demonstrated the existence of a mitochondrial network in cardiac and other tissues, e.g. diaphragm, soleus and vastus muscle, kidney and urinary bladder, in vivo. Confluent monolayers of synchronously beating embryonic chick heart cells were fixed, stained with a mitochondria-specific heavy metal complex (Pb-Cu citrate), and processed for either transmission electron microscopy (TEM) or scanning electron microscopy (SEM) and backscatter electron imaging (BSI). Both secondary and backscatter images revealed the presence of many thin, extremely elongate structures which in stereo views appeared as branching, anastomosing networks. TEM demonstrated localization of the electron dense stain to either nuclear or mitochondrial membranes, structures which were easily distinguished with SEM or BSI alone. These morphological results indicate that many mitochondria of the cultured heart muscle cell are interconnected and suggest that this morphological network may represent a parallel functional unit which maintains the energy state of the cell.
通过薄切片形态测量法测定，单层培养的鸡心脏细胞的线粒体占细胞胞质体积的比例相对较大（30%），并且其超微结构会根据细胞的不同功能状态而变化。由于重建实验已证明在心脏及其他组织（如体内的膈肌、比目鱼肌、股四头肌、肾脏和膀胱）中存在线粒体网络，因此开展了本研究以确定心脏细胞中线粒体的三维结构。将同步跳动的胚胎鸡心脏细胞汇合单层进行固定，用线粒体特异性重金属复合物（柠檬酸铅 - 铜）染色，然后进行透射电子显微镜（TEM）或扫描电子显微镜（SEM）及背散射电子成像（BSI）处理。二次电子图像和背散射电子图像均显示存在许多细小、极其细长的结构，在立体视图中呈现为分支、吻合的网络。TEM显示电子致密染色定位于核膜或线粒体膜，而单独使用SEM或BSI就能轻松区分这些结构。这些形态学结果表明，培养的心肌细胞中的许多线粒体相互连接，并且表明这种形态学网络可能代表一个维持细胞能量状态的平行功能单元。
