Schulze C, Firth J A
Department of Anatomy and Cell Biology, St. Mary's Hospital Medical School, Imperial College of Science, Technology and Medicine, London, UK.
Cell Tissue Res. 1993 Jan;271(1):145-54. doi: 10.1007/BF00297552.
Pericytes are cells of mesodermal origin which are closely associated with the microvasculature. Despite numerous studies little is known about their function. We have studied the relationship between pericytes and the endothelium in rat myocardial capillaries employing ultrastructural and immunogold techniques. 14% of the subendothelial cell membrane is covered by comparatively small pericytic cell processes. About half of these processes are completely embedded in basement membrane material, whereas the remaining half forms closer contacts with the endothelium. These contacts are devoid of anti-laminin immunogold label, a marker for basement membranes. A small fraction of these contacts has been identified as tight junctions resembling those seen between endothelial cells in capillaries of the same tissue. The remaining majority of junctions reveals a cleft of approximately 18 nm between the apposed membranes in which a succession of cleft-spanning structures can often be detected. It was also found that pericytic processes are preferentially located close to interendothelial junctions. We suggest that the high frequency of intimate junctions between pericytes and the endothelium and the preferential localisation near paracellular clefts may have functional significance.
周细胞是中胚层来源的细胞，与微血管密切相关。尽管有大量研究，但对其功能仍知之甚少。我们采用超微结构和免疫金技术研究了大鼠心肌毛细血管中周细胞与内皮细胞之间的关系。14%的内皮下细胞膜被相对较小的周细胞突起覆盖。这些突起中约一半完全嵌入基底膜物质中，而其余一半与内皮细胞形成更紧密的接触。这些接触部位没有抗层粘连蛋白免疫金标记，而抗层粘连蛋白免疫金标记是基底膜的标志物。这些接触中有一小部分已被鉴定为紧密连接，类似于同一组织毛细血管内皮细胞之间的紧密连接。其余大部分连接处，相邻膜之间有一个约18nm的间隙，在这个间隙中经常可以检测到一系列横跨间隙的结构。还发现周细胞突起优先位于内皮细胞间连接附近。我们认为，周细胞与内皮细胞之间紧密连接的高频率以及在细胞旁间隙附近的优先定位可能具有功能意义。
