Ojeda José L, Wong Wai P, Ip Yuen K, Icardo José M
Department of Anatomy and Cell Biology, University of Cantabria, Santander, Spain.
Anat Rec (Hoboken). 2008 Sep;291(9):1156-72. doi: 10.1002/ar.20729.
This work studies the structural and lectin-binding modifications experienced by the renal corpuscle of the African lungfish Protopterus dolloi during aestivation. The kidney of the aestivating animals was studied by light- and electron-microscopy, and by immunofluorescence methods. Upon aestivation, the renal corpuscles (RCs) undergo a marked size reduction, and all the structural RC components are affected. The parietal cells of Bowman's capsule lose their flattened appearance and adopt the organization of a stratified epithelium. The glomerular capillaries collapse. The podocytes approach each other. Concomitantly, the major processes between contiguous cells are lost, the rest of the major processes adopting a lamina-like configuration. The foot processes lose their regular arrangement, the filtration slits are difficult to observe, and the subpodocyte space disappears. The glomerular basement membrane (GBM) thickens enormously, increases the amount of amorphous material and of collagen, and round inclusions formed by amorphous material and coiled fibrils appear. The mesangial cells compact and form a dense network embedded in the subendothelial lamina of the GBM. The endothelial cells show numerous irregularities, establishing abnormal interrelationships with the mesangial cells. These modifications are accompanied by changes in the expression of the carbohydrate moieties, as indicated by the modifications in lectin-binding patterns. On the whole, these modifications thicken and compact the filtration barrier, thus reducing the filtration coefficient and allowing the organism to cope with dehydration. All these modifications are partially reversed during the first days of returning the animals to freshwater. The renal corpuscle appears to be a highly dynamic structure capable of modifying its architecture in response to environmental changes.
本研究探讨了非洲肺鱼多鳍鱼在夏眠期间肾小体所经历的结构和凝集素结合修饰。通过光学显微镜、电子显微镜和免疫荧光方法对夏眠动物的肾脏进行了研究。夏眠时，肾小体（RCs）明显缩小，所有肾小体结构成分均受到影响。鲍曼囊壁层细胞失去扁平外观，呈现复层上皮组织。肾小球毛细血管塌陷。足细胞相互靠近。与此同时，相邻细胞之间的主要突起消失，其余主要突起呈板层状结构。足突失去规则排列，滤过裂隙难以观察到，足细胞下间隙消失。肾小球基底膜（GBM）极度增厚，无定形物质和胶原蛋白含量增加，出现由无定形物质和卷曲纤维形成的圆形包涵体。系膜细胞致密化，形成嵌入GBM内皮下层的致密网络。内皮细胞出现许多不规则变化，与系膜细胞建立异常相互关系。这些修饰伴随着碳水化合物部分表达的变化，凝集素结合模式的改变表明了这一点。总体而言，这些修饰使滤过屏障增厚并致密化，从而降低滤过系数，使机体能够应对脱水。在动物返回淡水的最初几天，所有这些修饰会部分逆转。肾小体似乎是一种高度动态的结构，能够根据环境变化改变其结构。
