Congenital unilateral ureteropelvic junction obstruction of the rat: a useful animal model for human ureteropelvic junction obstruction?
OBJECTIVE
To investigate the expression of endothelin-1 (ET-1) and adrenomedullin (ADM) in the renal pelvis, stenotic ureteropelvic junction, and ureter of 20 male Wistar rats with congenital unilateral ureteropelvic junction obstruction; the normal contralateral kidneys served as controls. The molecular pathophysiology of congenital ureteropelvic junction obstruction is still unclear. The implication of altered peptidergic innervation is under discussion. Our study group has recently been able to demonstrate a significant increase in ET-1 and a significant decrease in ADM in prestenotic and stenotic tissue, but not in the remainder of the ureter, compared with controls.


METHODS
Twenty animals were killed, and samples of the renal pelvis, ureteropelvic junction, upper ureter, middle part of the ureter, and lower ureter were immediately snap-frozen and stored in liquid nitrogen. Total RNA was extracted, and subsequently 1 microg of RNA was reversely transcribed. mRNA expression of ET-1 and ADM was determined semiquantitatively using on-line polymerase chain reaction. The expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was determined to relate the specific mRNA expression to the expression of a housekeeping gene.


RESULTS
We found a significant increase in the expression of ET-1 in the obstructed junctions related to GAPDH (P <0.001). The expression of ADM, however, revealed no statistically significant differences. No differences at all could be detected in the tissue samples from the rest of the ureter.


CONCLUSIONS
Alterations in the local production of peptidergic neurotransmitters, especially ET-1, may contribute to the molecular pathogenesis of ureteropelvic junction obstruction. Results previously obtained in the stenotic tissue from children were confirmed in the stenotic tissue from the rat model. We hypothesize that the alterations are disease-, but not age-specific.
Miller
Joerg
J
Department of Urology, Justus-Liebig University of Giessen, Giessen, Germany.
Hesse
Michael
M
Diemer
Thorsten
T
Haenze
Joerg
J
Knerr
Ina
I
Rascher
Wolfgang
W
Weidner
Wolfgang
W
D000015:Abnormalities, Multiple / Q000235:genetics* / Q000378:metabolism; D053607:Adrenomedullin; D000818:Animals; D001284:Atrophy; D003199:Computer Systems; D003251:Constriction, Pathologic; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000096:biosynthesis / Q000235:genetics; D020869:Gene Expression Profiling; D006869:Hydronephrosis / Q000151:congenital* / Q000235:genetics / Q000378:metabolism; D007682:Kidney Pelvis / Q000002:abnormalities* / Q000378:metabolism; D008297:Male; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D011922:Rats, Mutant Strains; D017208:Rats, Wistar; D014513:Ureter / Q000002:abnormalities* / Q000378:metabolism; D014517:Ureteral Obstruction / Q000151:congenital* / Q000235:genetics / Q000378:metabolism
D019332:Endothelin-1; D010455:Peptides; D012333:RNA, Messenger; D053607:Adrenomedullin