The role of infection and free oxygen radical damage in reflux nephropathy: an experimental study.
OBJECTIVE
We compared the effects of sterile and infected urine on reflux nephropathy in rabbits with experimental vesicoureteral reflux.


METHODS
We used 2-month-old male New Zealand rabbits in this study. Group 1 (5 rabbits) served as the control, group 2 (7) was the vesicoureteral reflux plus sterile urine group and group 3 (8) was the reflux plus infected urine group. Cystography and 99mTc-dimercapto-succinic acid renal scintigraphy were performed before the reflux procedure. To create unilateral vesicoureteral reflux the roof of the right intravesical ureter was incised. Escherichia coli suspension (2 ml.), 105 E. coli in 1 ml.) was introduced into the bladder in addition to the reflux procedure in group 3. Right vesicoureteral reflux was confirmed by cystography 2 weeks after reflux. Dimercapto-succinic acid scintigraphy was performed at 3 weeks and the animals were sacrificed and examined. Free oxygen radical damage was investigated by measuring malondialdehyde levels in renal tissue. ANOVA and Scheffe's test were used for statistical analysis.


RESULTS
Histopathological evaluation of the right kidney from group 2 rabbits showed mild interstitial fibrosis and mononuclear cell infiltration. The right kidney from group 3 rabbits showed apparent periglomerular fibrosis, tubular atrophy and dilatation, severe interstitial scarring and fibrosis with mononuclear cell infiltrate. There were marked histopathological changes in the right kidney of group 3 rabbits. The absolute percent dose uptake was unchanged in group 2 rabbits (p >0.05). There was significantly decreased uptake in refluxing kidneys and increased uptake in the contralateral nonrefluxing kidneys after vesicoureteral reflux in group 3 rabbits. The malondialdehyde level in the right renal tissue of group 3 was significantly higher than that in controls and in group 2 (p <0.05). The malondialdehyde level in the sterile reflux group did not differ significantly from that in the control group (p >0.05).


CONCLUSIONS
The results of this study show that free oxygen radical damage in the presence of infection has an important role in reflux nephropathy.
Okur
Hamit
H
Department of Pediatric Surgery, Erciyes University Medical School, Kayseri, Turkey.
Köse
Ozkan
O
Kula
Mustafa
M
Oztürk
Figen
F
Muhtaroğlu
Sabahattin
S
Sümerkan
Bülent
B
D000818:Animals; D005609:Free Radicals; D007674:Kidney Diseases / Q000209:etiology* / Q000473:pathology; D008297:Male; D011817:Rabbits; D017382:Reactive Oxygen Species; D014552:Urinary Tract Infections / Q000150:complications*; D014718:Vesico-Ureteral Reflux / Q000150:complications*
D005609:Free Radicals; D017382:Reactive Oxygen Species