Chelidze P V, Dzidziguri D V, Zarandiia M A, Georgobiani N M, Tumanishvili G D
Tsitologiia. 1993;35(10):3-12.
By means of stereological and morphometrical analysis, the ultrastructure of nucleoli in epitheliocytes of mouse kidney cortex proximal tubuli has been studied. In accordance to the nucleolar composition, three main groups of nephrocytes with different levels of rRNA and protein synthesis were defined. Functional heterogeneity of proximal tubuli epithelium was established by correlation between different variants of ultrastructural organization of nucleoli and the total RNA synthesis activity, determined by 3H-uridine incorporation intensity. It has been shown that a greater part of cells (about 52%) in the nephron proximal section, which is characterized by slow RNA synthesis, causing a low functional activity of these cells, presumably represents a reparative cellular reserve. Such cells, defined as the 1st group cells, have resting, ring-shaped nucleoli with one fibrillar centre, and nucleoli similar to the ring-shaped ones but containing 2-3 fibrillar centres. Nucleoli of the 2nd group of nephrocytes (about 37%), most actively incorporating labeled precursor, contain 4-6 fibrillar centres. Their structural organization is closer to the reticular type of nucleoli. The 3rd most actively labeled group of nephrocytes includes cells with typical reticulated nucleoli. The number of fibrillar centres in the reticulated nucleoli is much higher (18-22) than in the 1st and 2nd groups of nephrocytes. Structural and functional polymorphism of nephrocytes was revealed not only in the proximal part of one nephron. During the increase in functional activity of nephrocytes, caused by unilateral nephrectomy, the quantitative correlation between cells related to these different groups was seen to change. The number of cells of the 1st group decreased by 24%, whereas that in the 2nd and 3rd groups increased by 9 and 15%, respectively. Nucleoli with 2-3 fibrillar centres are considered as transitional forms between the inactive ring-shaped nucleoli and the active reticulated nucleoli. Differences in the ultrastructure of nucleoli may be considered as an evidence of functional heterogeneity of nephrocytes within the proximal segment of nephron.
通过体视学和形态计量学分析，对小鼠肾皮质近端小管上皮细胞中核仁的超微结构进行了研究。根据核仁组成，确定了具有不同rRNA和蛋白质合成水平的三类主要肾细胞。通过核仁超微结构组织的不同变体与由3H-尿苷掺入强度测定的总RNA合成活性之间的相关性，确立了近端小管上皮的功能异质性。结果表明，肾单位近端部分中较大比例的细胞（约52%）以RNA合成缓慢为特征，导致这些细胞的功能活性较低，推测代表修复性细胞储备。这类细胞被定义为第1组细胞，具有静止的、带有一个纤维中心的环形核仁，以及类似于环形核仁但含有2-3个纤维中心的核仁。第2组肾细胞（约37%）最活跃地掺入标记前体，其核仁含有4-6个纤维中心。它们的结构组织更接近网状核仁类型。第3组最活跃标记的肾细胞包括具有典型网状核仁的细胞。网状核仁中的纤维中心数量比第1组和第2组肾细胞中的要高得多（18-22个）。肾细胞的结构和功能多态性不仅在一个肾单位的近端部分表现出来。在单侧肾切除引起的肾细胞功能活性增加过程中，与这些不同组相关的细胞之间的数量相关性发生了变化。第1组细胞数量减少了24%，而第2组和第3组细胞数量分别增加了9%和15%。具有2-3个纤维中心的核仁被认为是无活性环形核仁和活性网状核仁之间的过渡形式。核仁超微结构的差异可被视为肾单位近端段内肾细胞功能异质性的证据。
