Protective effects of cranberries on infection-induced oxidative renal damage in a rabbit model of vesico-ureteric reflux.
OBJECTIVE
To evaluate the protective effects of cranberry fruit, which have known antioxidant effects, on infection-induced oxidative renal damage in a rabbit model of vesico-ureteric reflux (VUR).


METHODS
In all, 36 New Zealand male rabbits were divided into five groups, with a sham operation in four rabbits serving as the control (group 1). To create unilateral VUR the roof of the left intravesical ureter was incised, and VUR confirmed 2 weeks after surgery. In all, 32 rabbits with VUR were divided into four groups; 2, VUR alone (with sterile urine); 3, a group infected with Escherichia coli; 4, with intravesical E. coli instillation but fed cranberries; and 5, intravesical E. coli instillation plus an intraperitoneal injection with melatonin group. At 3 weeks after surgery the rabbits were killed, the kidneys obtained and examined histopathologically to evaluate inflammation, fibrosis and tubular changes. Oxidative renal damage was evaluated by measuring malondialdehyde in the renal tissue.


RESULTS
Grossly, the refluxing kidney was larger than the contralateral normal kidney, and the refluxing ureter was dilated and tortuous. Microscopy of tissues from the kidneys in group 3 showed apparent periglomerular mononuclear cell infiltration, tubular dilatation and atrophy, and interstitial fibrosis. The kidneys from groups 2, 4 and 5 showed mild mononuclear cell infiltration with no interstitial fibrosis. The level of malondialdehyde in the kidneys of group 3 was significantly higher than that in group 2, 4 and 5 (P < 0.05); the level in groups 4 and 5 did not differ significantly from that in group 2.


CONCLUSIONS
This study shows that cranberries have an anti-inflammatory effect through their antioxidant function and might prevent infection-induced oxidative renal damage. Thus, clinically cranberries might be used as a beneficial adjuvant treatment to prevent damage due to pyelonephritis in children with VUR.
Han
Chang Hee
CH
Department of Urology, College of Medicine, the Catholic University of Korea, Seoul, Korea.
Kim
Soo Hwan
SH
Kang
Sung Hak
SH
Shin
Ok Ran
OR
Lee
Hae Kyung
HK
Kim
Hee Jeong
HJ
Cho
Yong-Hyun
YH
D000818:Animals; D000975:Antioxidants / Q000627:therapeutic use*; D005609:Free Radicals; D007674:Kidney Diseases / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D008517:Phytotherapy; D011817:Rabbits; D029799:Vaccinium macrocarpon; D014718:Vesico-Ureteral Reflux / Q000150:complications*
D000975:Antioxidants; D005609:Free Radicals; D008315:Malondialdehyde