Tissue damage and regeneration of ureteric smooth muscle in rats with obstructive uropathy

Abstract

Objective To investigate regeneration in obstructed ureters and to elucidate the role of hyperplasia in the thickening of the smooth muscle layer in the late stages of complete ureteric obstruction. Materials and methods The expression of Ki‐67 antigen, c‐Fos, c‐Jun and c‐Myc in the smooth muscle layer of obstructed ureters was determined using immunohistochemistry in 40 Sprague‐Dawley rats. After unilateral ligation of the ureter, five rats each were killed for examination at 1, 3, 7, 10, 14, 21, 28 and 42 days after ligation; five rats that underwent a sham operation were also examined as controls. Results The severity of hydroureter and thickening of the smooth muscle layer progressed consistently in the ligated ureters, but no mitosis was detected in myocytes within 14 days of ligation. Fibrosis in the smooth muscle layer appeared 21 days after ligation and progressed. There was no expression of Ki‐67 antigen and oncoproteins until 14 days after ligation. The expression of Ki‐67 and c‐Myc increased gradually to a peak after 28 days, then declined. However, the expression of c‐Fos and c‐Jun was low and transient. Conclusion Cell regeneration is impaired in the damaged muscle layer of obstructed ureters. Only hypertrophy and not hyperplasia of the smooth muscle layer developed during the course of complete ureteric obstruction in this rat model of obstructive uropathy.

Atorvastatin ameliorates tissue damage of obstructed ureter in rats

“…It may lead to severe renal and ureteric injury (Chuang et al, 1995;Chuang et al, 1998;Pais et al, 2007). The aggravation of hydronephrosis results in tubulo-interstitial fibrosis in the kidney, replacement of the renal parenchyma with scar tissue, and the progressive loss of nephrons (Pais et al, 2007).…”

Urinary Obstruction: Ureteral Obstruction

“…At the cellular level, an influx of leukocytes into the obstructed kidney results in interstitial fibrosis and glomerulosclerosis [7]. In a rat model, the ureter similarly develops fibrosis over a period of 5 weeks [8]. The effect on the kidney and ureter in the clinical patient with obstructive ureteral disease is unknown, but suspected to be similar.…”

Over-expression of apoptosis-related proteins contributes to muscular damage in the obstructed ureter of the rat

“…Although the degeneration and regeneration of ureteric smooth muscle cells during obstructive uropathy has been studied [3], the role of apoptosis and apoptosis-related proteins (Myc, Bax, Bcl-2, and Bcl-X L ) in tissue damage to the smooth muscle layer during the development of obstructive uropathy has rarely been reported.…”