Korean J Urol.  2013 Apr;54(4):266-270.

Expression of Aquaporin-3 in Ipsilateral Rat Kidney With Unilateral Partial Ureteral Obstruction

• Lee JY
• Shin JH
• Song KH
• Lim JS
• Sul CK

Abstract

PURPOSE
Aquaporin (AQP), a protein located in the cellular membrane, allows rapid passage of water across the cell membrane. Various AQP subtypes have been associated with ureteral obstruction. In particular, AQP3 has two functions: water and glycerol transport. The aim of this study was to investigate the expression of AQP3 in the ipsilateral rat kidney in unilateral partial ureteral obstruction (UPUO).
MATERIALS AND METHODS
Sprague-Dawley rats (n=30, 200-250 g) were divided into two groups. A sham operation was performed in the control group (n=10) and UPUO of the left upper ureter with a silicone tube was induced in the UPUO group (n=20). The left kidney was obtained from both groups 7 days after the operations. The kidney specimens underwent immunofluorescent staining with AQP3 monoclonal antibody, and the density of AQP3 in the tissue was measured with an image analyzer.
RESULTS
In the UPUO group, thinning of the epithelial layer and infiltration of inflammatory cells was seen along with the localized expression of AQP3 in the basolateral aspect of the principal collecting duct cells. The mean optical density of AQP3 was significantly lower in the UPUO group than in the control group (100.9+/-17.5 compared with 131.7+/-16.9; p<0.001).
CONCLUSIONS
These results suggest that a decrease in the expression of AQP3 may be the result of a urinary stasis reaction caused by UPUO in response to local and intrarenal factors. These changes suggest that AQP3 may have a pathophysiological role in UPUO.

Keyword

Aquaporin 3; Ureteral obstruction

MeSH Terms

Animals
Aquaporin 3
Cell Membrane
Glycerol
Kidney
Membranes
Rats
Rats, Sprague-Dawley
Salicylamides
Silicones
Ureter
Ureteral Obstruction
Aquaporin 3
Glycerol
Salicylamides
Silicones

Figure

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  FIG. 1 Hematoxylin and eosin staining. Thinning of epithelial thickness, dilation of collecting ducts/distal tubules, and infiltration of inflammatory cells were observed in the group with unilateral partial ureteral obstruction (C, ×20; D, ×200) but not in the control group (A, ×20; B, ×200).

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  FIG. 2 Immunofluorescent staining for aquaporin (AQP)3 in the control group (A) and in the group with unilateral partial ureteral obstruction (UPUO) (B). AQP3 is located mainly in the basolateral aspect of principal cells (A-1: magnification of A, ×680). The immunoreactive expression of AQP3 was significantly weaker in the UPUO group than in the control group.

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  FIG. 3 Optical density of aquaporin (AQP)3 observed after immunofluorescent staining in the control group and in the group with unilateral partial ureteral obstruction (UPUO). Data are expressed as mean±standard deviation. a:p<0.001.

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