Abstract

Objective: The aim of this experimental study is to determine all histopathological alterations in the early, and late stages of UPJ obstruction caused by partial and complete unilateral obstruction in ipsilateral and particularly contralateral kidney and to evaluate the progression of these alterations.

Methods: Forty-two female Sprague Dawley rats were assigned randomly into three groups (each containing 14 rats) according to the degree of unilateral UPJ obstruction as Group I, sham operation; Group II, partial , and Group III, complete UPJ obstruction categories . Half of the rats in each group were sacrificed after two weeks and while the other half were sacrificed after eight weeks and bilateral nephrectomy was performed. Tissue samples were prepared and processed according to routine light microscopic tissue processing.

Results: UPJ obstruction led to cystic dilatation of the renal pelvis, glomerular collapse, dilation of proximal, distal and collecting tubules and necrotic cell deposit in the tubule lumen, degeneration of the epithelial cells, interstitial edema, inflammation and fibrosis in ipsilateral kidneys. Severity of these histopathological alterations depended on the degree and duration of the obstruction. UPJ obstruction also led to histopathological alterations on the contralateral kidneys such as cystic dilatation of the renal pelvis, glomerular collapse, epithelial degeneration of the proximal, distal and collecting tubules and interstitial edema and inflammation. Although severity of these histopathological alterations did not depend on the degree of obstruction, severity of obstruction decreased depending on the duration of the obstruction.

Conclusion: UPJ obstruction leads to renal damage on the contralateral kidney in the early period, but this renal damage is reduced in the late period. Further investigations are needed to investigate the mechanism of the renal damage seen in the early and the improvement in the late period.