Portal de Periódicos da CAPES

Methods for imaging renal tubule cells

1986; Elsevier BV; Volume: 30; Issue: 2 Linguagem: Inglês

10.1038/ki.1986.171

1523-1755

Kevin Strange, Kenneth R. Spring,

Connexins and lens biology

Functional studies of renal tubules by conventional techniques, such as isotopic tracer or electrophysiologic methods, are limited both by epithelial cellular heterogeneity and by technical considerations, such as paracellular ion flows and unstirred layer effects. Although many approaches have been devised to correct for these complications, it has been difficult to measure the transport properties of individual nephron cells. The functional characteristics of single cells in renal tubules can now be directly assessed by quantitative light microscopic techniques. This approach involves the measurement of the cell volume changes which occur when solution osmolality or ionic composition are altered. The judicious use of such experiments in combination with the application of specific transport inhibitors allows determination of cell membrane water and ion permeabilities as well as characterization of the ion transporters in the individual cell membranes which mediate transepithelial solute movements. The mechanisms by which renal tubule cells maintain their volume and ionic composition in the face of dramatically varying solute loads and transcellular transport rates may also be determined. Visualization of specific cell types in a heterogenous epithelium, such as the cortical collecting tubule, may make it feasible to conduct both optical and microelectrode studies on the same cell. Furthermore, the use of low light level video methods in conjunction with fluorescent probes should enable study of renal tubule cell biological processes such as receptor—ligand interaction, insertion and retreival of membrane transport proteins, and intracellular events such as organelle movement, endoand exocytosis, and turnover of intracellular constituents. Isolated renal tubules are well suited for light microscopic study. The absence of connective tissue or other supporting structures enables acquisition of high contrast images of the tubule cells. The small diameter (typically 30 m) of the tubules eliminates unstirred layers within the lumen of the tubule. Careful design of the bath chamber permits the virtual elimination of unstirred layers on the basolateral cell surface. Renal tubules offer the opportunity to visualize epithelial cells both in the conventional en face manner as well as in lateral cross section. This article will review the principles and techniques for quantitative light microscopy of isolated renal tubular epithelial cells.