| Abstract: |
SUMMARY AND CONCLUSIONObstructive uropathy caused by ureteric obstruction is one of the most common diseases of the urinary tract. Ureteral obstruction can be resulted from stone formation, post inflammatory stricture or bilharizial stricture. This obstruction is commonly unilateral and can cause severe renal and ureteric injury. Several experimental studies have been done to investigate obstructive uropathy however, most of these studies have focused on the functional and dynamic changes.So, the objective of this work was to study the possible histological changes in the ureter and kidney resulting from induction of ipsilateral ureteral obstruction. For this purpose, forty male adult albino rats (170 - 230 gm.) were utilized. The animals were divided into four groups (10 animals each). Group A (control group) that underwent a sham operation. Groups B, C and D were scarified 7, 14 and 21 days post-operative respectively. The animals were anaesthetized. The specimens from the ureters and kidneys were immersed in suitable fixatives for light and electron microscopic studies. The obtained sections were stained with H & E stain to study the general structure of the kidney and ureter, and Mallory’s Trichrome stain for collagen. Ultrathin sections were examined by electron microscope to study the changes at the cellular level.Histological examination of the kidney of adult rats 1week after complete ligation of its ureter showed some renal corpuscles with enlarged glomeruli and narrow Bowman’s spaces. Also, there was moderate dilatation of some convoluted and collecting tubules. The proximal convoluted tubules were more affected. Their epithelial lining showed vacuolated cytoplasm and loss of the apical microvilli.Examination of adult rat kidney 2 weeks after complete ligation of its ureter showed shrinkage of some glomeruli with widening of their Bowman’s spaces and distortion of the foot processes of some podocytes. There was more dilatation of the convoluted tubules with flattening of the tubular epithelium. The lining epithelium of some convoluted tubules showed many vacuoles and condensed heterochromatic nuclei. Also, widening of the interstitium by infiltrating cells and deposited collagen fibrils was noticed.Examination of the adult rat kidney 3 weeks after complete ligation of its ureter showed the presence of some distorted glomeruli. Basal lamina of the glomerular capillaries appeared thickened with distortion of the foot processes of some podocytes. Also, there were collapse of many tubules and dilatation of others. The cells lining tubules had electron-dense, indented nuclei and many disrupted mitochondria in addition to a thick irregular basement membrane.Moreover, examination of the proximal segment of the adult rat ureter showed different histological changes that became apparently worse with the increase in the duration of obstruction. One week after obstruction, there was an increase in the thickness of all layers of the ureteral wall with some desquamated epithelial cells in the lumen. Cellular infiltration in the lamina propria was also observed. The smooth muscle fibers appeared with electron dense nuclei and vacuolated cytoplasm. There were many layers of collagen fibrils in-between the muscle fibers and in the adventitia.On the other hand, 2weeks after obstruction the proximal segment of the ureter appeared with dilated lumen and thick adventitia. The density of collagen fibers was increased in both lamina propria and adventitia. The muscle cells appeared electron dense and widely separated by ground substance and collagen fibrils. Some of them showed few organelles and the others had numerous mitochondria.In addition, more deposition of collagen in the adventitia occurred 3weeks after obstruction. Also, some electron dense atrophied smooth muscle cells were demonstrated. They were widely separated by large amounts of collagen fibrils.In conclusion, the kidney and the proximal segment of the ureter showed histological changes that progressed with the increased duration of obstruction of the ipsilateral ureter. Early diagnosis of obstructive uropathy may allow the urologist to early correct the structural abnormality and prevent further deterioration in the renal function. Placing the patient on antibiotic prophylaxis is also recommended because the changes occurred due to combination of obstruction and infection. Also, the status of the ureter component remains important if surgical repair is to be considered.
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