Partial Ureteric Obstruction in the Pubescent Rat. I. Long-Term Effects on Renal Function

Abstract

A partial obstruction of the left ureter was created in six-week-old rats. The effects on renal function were studied after three, nine and 15 weeks, first in normal hydration, and then after extracellular volume expansion. Moderate hydronephrosis without parenchymal weight reduction developed within three weeks. The hydronephrotic kidney i) excreted during normal hydration less urine and sodium than the intact one, because of increased reabsorption, ii) was capable of reacting fully on volume expansion and iii) had, after volume expansion, a higher renal blood flow and GFR but also a higher reabsorption of water, sodium, potassium and osmoles, resulting in excretions similar to those on the intact side. The differences noted were small (less than 20%) except for sodium excretion. The hydronephrotic kidney seemed to tolerate an increase in ureteral resistance better than the intact one would do. There were no significant differences between the three, nine and 15-week groups, with regard to the effects on the hydronephrotic kidney. Thus, except for a tendency to sodium retention, the effects of partial ureteric obstruction in young rats seem to be relatively harmless and do not increase with time.

The early and late period alterations on the contralateral renal parenchyma secondary to unilateral ureteropelvic junction obstruction: experimental study

“…Bizim çalışmamızda da; daha önceki çalışmalara (7,8,13,15,21) benzer şekilde, ÜPB tıkanıklığının aynı taraf böbrekte; renal pelviste kistik dilatasyon, glomerüler büzüşme, glomerüloskleroz, glomerüler kapiller yatakta konjesyon, tübüler atrofi ve dilatasyon, tübül lümeninde nekrotik hücre birikimleri, tübüler epitel hücrelerinde hasar, intertisyel fibrozis, ödem, inflamasyon gibi histopatolojik değişikliklere yol açtığı gösterilmiştir. Buna karşın literatürde (8,23,28) , ÜPB tı-kanıklığı olan böbreklerden yapılan biyopsilerin % 16 ila % 54'ünde histopatolojik görünümün normal olduğu bildirilmiştir.…”

“…Yapılan çeşitli çalışmalarda (7,8,13,15,21) tam ya da kıs-mi ÜPB tıkanıklığına bağlı olarak etkilenen böbrekte gelişen histopatolojik değişiklikler ortaya konmuştur. Bu histopatolojik değişikliklerden de renal kan akı-mının azalmasına yani iskemiye bağlı olarak üretimi artan bazı mediatörlerin ve serbest oksijen radikallerinin sorumlu olduğu gösterilmiştir (1,3,27,30) .…”

Partial Ureteric Obstruction in the Pubescent Rat

“…The persistent patency of the ureter is evidenced by the mod erate effects on renal morphology and function, despite subjection to obstruction up to 1 year [1-3, 5, 16]. The permanency of obstruction-to-flow has been verified by perpetually raised intrapelvic pressure and ureteral resis tance [5,17], by prolonged renopelvic transit time on isotope renograms [3] and by persistent enlargement of pelvic volume and ureteric diameter [5] until release of the obstruction [18], In the present experiments, the pelvis became consid erably enlarged, as usually happens with this obstructive procedure. However, the microstructure was only slightly affected, a finding which agrees with previous studies of partial ureteric obstruction [4,19].…”

“…Partial obstruction is much commoner and is quite a different disorder. In an extensive series of stud ies, we have examined the long-term effects of unilateral partial obstruction on the rat kidney and found an obvious difference depending on when the obstruction was created -in the neonatal period [1][2][3], in the wean ling age [4] or in puberty [5]. In the latter study, only the renal function effects were examined, 3-15 weeks after creation of the partial obstruction.…”

Renal Tissue Endothelin in Long-Term Complete Ureteric Obstruction in the Young Rat

“…3-week-old rats [10,23], or in pubescent age, i.e. 6-week-old rats [11,24], This was espe cially valid for tubular functions but also for renal blood flow and glomerular filtration. It is thus highly probable that the endothelin response varies with age at obstruc tion.…”