McGuffee L J, Mercure J, Little S A
Department of Pharmacology, School of Medicine, University of New Mexico, Albuquerque 87131.
Anat Rec. 1991 Apr;229(4):499-504. doi: 10.1002/ar.1092290410.
In this report, we present a three-dimensional computer assisted reconstruction study from serial thin sections through a rabbit renal artery smooth muscle cell. In a series of 32 consecutive thin (100-nm) sections, one longitudinally oriented cell was followed and photographed in alternating sections. The profiles of the cell surface and dense bodies were reconstructed from these 16 planes and the distribution, size, shape, and spatial relationships among these components was examined. The reconstructed images showed that the cell decreases in diameter from its widest region in the center to the two ends in a step-wise taper. Within the cell, dense bodies are numerous. Relative to the cell axes, a membrane associated dense body (MDB) can be less than or equal to 3.5 microns long, 0.25 micron wide, and may extend up to 2 microns in depth. While the MDB profile in one section may be aligned with the long axis of the cell, in an adjacent section the same dense body may appear almost circular or wedge shaped. The same is true of cytoplasmic dense bodies (CDBs). Compared with MDBs, CDBs are smaller in all dimensions. Some, but not all, CDBs line up in strings oriented with the long axis of the cell. The continuity of dense bodies over considerable cell depth and their change in shape may have important implications for integration of contractile activity and for transmitting passive tension to the extracellular matrix.
在本报告中，我们展示了一项通过对兔肾动脉平滑肌细胞的连续薄切片进行三维计算机辅助重建的研究。在一系列连续的32个薄（100纳米）切片中，追踪一个纵向排列的细胞，并在交替的切片中进行拍照。从这16个平面重建细胞表面和致密体的轮廓，并检查这些成分之间的分布、大小、形状和空间关系。重建图像显示，细胞直径从中心最宽处向两端呈逐步变细。细胞内致密体众多。相对于细胞轴，膜相关致密体（MDB）长度可小于或等于3.5微米，宽度为0.25微米，深度可达2微米。虽然一个切片中的MDB轮廓可能与细胞长轴对齐，但在相邻切片中，同一个致密体可能几乎呈圆形或楔形。细胞质致密体（CDB）也是如此。与MDB相比，CDB在所有维度上都较小。一些（但不是全部）CDB沿细胞长轴方向排列成串。致密体在相当大的细胞深度上的连续性及其形状变化可能对收缩活动的整合以及将被动张力传递到细胞外基质具有重要意义。
