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Functionally induced changes in water transport in the proximal tubule segment of rat kidneys.

Faarup P, Holstein-Rathlou NH, Nørgaard T, Harrison AP, Bastholm L, Thatt L, Johansen FF, Hegedüs V - Int J Nephrol Renovasc Dis (2011)

Bottom Line: However, in the second segment, a special cellular phenomenon was constantly present, comprising a significant intercellular space that was easily identified using a light microscope.In the third segment, in which the presence of basolateral interdigitations is minimal, the small lateral space, which was found to be present in cryopreparations between neighboring cells from the normal kidney, was found to be enlarged by heavy salt loading of short duration.It is concluded that these cryotechniques demonstrate quantitative structural variations between superficial and deep nephrons, as well as the presence of extracellular areas between the cells of the second and the third segment, representing a structural background for the essential transport of water from the proximal tubules to the peritubular capillaries.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences, Panum Institute University of Copenhagen.

ABSTRACT
To eliminate freezing artifacts in the proximal tubule cells, two cryotechniques were applied to normal rat kidneys, ie, freeze substitution and special freeze drying. In addition, salt depletion and salt loading were applied to groups of rats to evaluate whether the segmental structure of the proximal tubule could be altered. In the superficial part of the renal cortex of normal kidneys, the typical first segment structure in the proximal tubule was generally present in the early postglomerular fraction of the tubule. However, in the second segment, a special cellular phenomenon was constantly present, comprising a significant intercellular space that was easily identified using a light microscope. In the third segment, in which the presence of basolateral interdigitations is minimal, the small lateral space, which was found to be present in cryopreparations between neighboring cells from the normal kidney, was found to be enlarged by heavy salt loading of short duration. It is concluded that these cryotechniques demonstrate quantitative structural variations between superficial and deep nephrons, as well as the presence of extracellular areas between the cells of the second and the third segment, representing a structural background for the essential transport of water from the proximal tubules to the peritubular capillaries.

No MeSH data available.


A freeze-dried normal kidney, vitally stained using methylene blue revealing the superficial cortex.Notes: The lumen of some S1 segments were stained by the intravenously injected methylene blue, which filtered through the glomerulus, whereas other S1 loops and later tubular fractions of the nephrons do not contain any stain in the lumen. Their tissue is only stained from the capillary side. Only in the S2 segments can a radial, cytoplasmic striation be seen, demonstrating a space between the basolateral membranes among S2 cells in the functioning kidney. The nuclei of the tubular cells are unstained in this preparation. D represents the distal tubule, GL denotes the glomerulus and H indicates the ascending branch of the loop of Henle, C denotes a capillary The scale bar represents 25 μm.
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f3-ijnrd-4-073: A freeze-dried normal kidney, vitally stained using methylene blue revealing the superficial cortex.Notes: The lumen of some S1 segments were stained by the intravenously injected methylene blue, which filtered through the glomerulus, whereas other S1 loops and later tubular fractions of the nephrons do not contain any stain in the lumen. Their tissue is only stained from the capillary side. Only in the S2 segments can a radial, cytoplasmic striation be seen, demonstrating a space between the basolateral membranes among S2 cells in the functioning kidney. The nuclei of the tubular cells are unstained in this preparation. D represents the distal tubule, GL denotes the glomerulus and H indicates the ascending branch of the loop of Henle, C denotes a capillary The scale bar represents 25 μm.

Mentions: The cellular structure of the proximal tubule in the cryopreparations of normal kidneys was consistently different from the morphology seen in similar specimens, for which no cryotechnique was employed during tissue preparation. In S1, represented by the immediate postglomerular tubular neck region, the tall cells, with a high brush border and a small tubular lumen, were present preferentially in the superficially located nephrons (see later parts of this section concerning the quantitative evaluation of cell types in the differently located nephrons, and Figures 1 and 2). However, in the juxtamedullary nephrons, S2-like tubular cells replaced the typical S1 cellular structure in the postglomerular neck region. Moreover, it is essential to note here that the structure of the segmentally identical tubular cells should be similar for the two types of cryopreparations applied, ie, the freeze-substitution technique, compared with the freeze-drying technique (Figures 1–3).


Functionally induced changes in water transport in the proximal tubule segment of rat kidneys.

Faarup P, Holstein-Rathlou NH, Nørgaard T, Harrison AP, Bastholm L, Thatt L, Johansen FF, Hegedüs V - Int J Nephrol Renovasc Dis (2011)

A freeze-dried normal kidney, vitally stained using methylene blue revealing the superficial cortex.Notes: The lumen of some S1 segments were stained by the intravenously injected methylene blue, which filtered through the glomerulus, whereas other S1 loops and later tubular fractions of the nephrons do not contain any stain in the lumen. Their tissue is only stained from the capillary side. Only in the S2 segments can a radial, cytoplasmic striation be seen, demonstrating a space between the basolateral membranes among S2 cells in the functioning kidney. The nuclei of the tubular cells are unstained in this preparation. D represents the distal tubule, GL denotes the glomerulus and H indicates the ascending branch of the loop of Henle, C denotes a capillary The scale bar represents 25 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3108790&req=5

f3-ijnrd-4-073: A freeze-dried normal kidney, vitally stained using methylene blue revealing the superficial cortex.Notes: The lumen of some S1 segments were stained by the intravenously injected methylene blue, which filtered through the glomerulus, whereas other S1 loops and later tubular fractions of the nephrons do not contain any stain in the lumen. Their tissue is only stained from the capillary side. Only in the S2 segments can a radial, cytoplasmic striation be seen, demonstrating a space between the basolateral membranes among S2 cells in the functioning kidney. The nuclei of the tubular cells are unstained in this preparation. D represents the distal tubule, GL denotes the glomerulus and H indicates the ascending branch of the loop of Henle, C denotes a capillary The scale bar represents 25 μm.
Mentions: The cellular structure of the proximal tubule in the cryopreparations of normal kidneys was consistently different from the morphology seen in similar specimens, for which no cryotechnique was employed during tissue preparation. In S1, represented by the immediate postglomerular tubular neck region, the tall cells, with a high brush border and a small tubular lumen, were present preferentially in the superficially located nephrons (see later parts of this section concerning the quantitative evaluation of cell types in the differently located nephrons, and Figures 1 and 2). However, in the juxtamedullary nephrons, S2-like tubular cells replaced the typical S1 cellular structure in the postglomerular neck region. Moreover, it is essential to note here that the structure of the segmentally identical tubular cells should be similar for the two types of cryopreparations applied, ie, the freeze-substitution technique, compared with the freeze-drying technique (Figures 1–3).

Bottom Line: However, in the second segment, a special cellular phenomenon was constantly present, comprising a significant intercellular space that was easily identified using a light microscope.In the third segment, in which the presence of basolateral interdigitations is minimal, the small lateral space, which was found to be present in cryopreparations between neighboring cells from the normal kidney, was found to be enlarged by heavy salt loading of short duration.It is concluded that these cryotechniques demonstrate quantitative structural variations between superficial and deep nephrons, as well as the presence of extracellular areas between the cells of the second and the third segment, representing a structural background for the essential transport of water from the proximal tubules to the peritubular capillaries.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences, Panum Institute University of Copenhagen.

ABSTRACT
To eliminate freezing artifacts in the proximal tubule cells, two cryotechniques were applied to normal rat kidneys, ie, freeze substitution and special freeze drying. In addition, salt depletion and salt loading were applied to groups of rats to evaluate whether the segmental structure of the proximal tubule could be altered. In the superficial part of the renal cortex of normal kidneys, the typical first segment structure in the proximal tubule was generally present in the early postglomerular fraction of the tubule. However, in the second segment, a special cellular phenomenon was constantly present, comprising a significant intercellular space that was easily identified using a light microscope. In the third segment, in which the presence of basolateral interdigitations is minimal, the small lateral space, which was found to be present in cryopreparations between neighboring cells from the normal kidney, was found to be enlarged by heavy salt loading of short duration. It is concluded that these cryotechniques demonstrate quantitative structural variations between superficial and deep nephrons, as well as the presence of extracellular areas between the cells of the second and the third segment, representing a structural background for the essential transport of water from the proximal tubules to the peritubular capillaries.

No MeSH data available.