Protective effects of cranberries on infection‐induced oxidative renal damage in a rabbit model of vesico‐ureteric reflux

Abstract

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). MATERIALS AND 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.

Consumption of cranberry polyphenols enhances human γδ-T cell proliferation and reduces the number of symptoms associated with colds and influenza: a randomized, placebo-controlled intervention study

“…Drawing firm conclusions about the role cranberry plays in cytokine production is premature, yet the data suggest that cranberry contributes to an anti-inflammatory effect. Cranberry proanthocyanidins have been suggested as being anti-inflammatory in in vitro studies [38,39] and in rabbits [7]. One human intervention study showed that the level of urinary IL-6 was reduced in pregnant women who consumed cranberry juice compared to a placebo [8], yet other cytokines measured in that study did not achieve statistical significance, perhaps due to the small n of each group.…”

“…Four studies have shown the effects of cranberry on immune function in diverse ways: in a rabbit model of infection-induced oxidative renal damage, cranberry reduced inflammation [7]; consumption of a cranberry beverage in a human intervention study resulted in a reduction in pathogen in 42% of the subjects without altering normal vaginal microbiota [6]; lower levels of urinary IL-6 were found in pregnant women after drinking cranberry juice for at least 3 days [8]; and an enhanced generation of anti-lymphoma antibodies was detected in an immuno-competent mouse model of lymphoma [9]. Recent studies have shown effectiveness of cranberry in reducing reoccurrence of urinary tract infections [10-12].…”

Urodynamic and Histological Changes in a Sterile Rabbit Vesicoureteral Reflux Model

“…Although rats are more economical than larger animals, the latter are much easier to handle. Moreover, the surgical procedure of open bladder incision of the intravesical ureteral tunnel is well established in the rabbit (5, 10). …”

Prevention of Urinary Tract Infections with Vaccinium Products

“…However, as with anthocyanins glycosides, that may contribute to the clinical symptom‐improving effect of cranberry preparaions (Hidalgo et al, 2012), plasma and urine concentrations of the co‐active compounds will be very low (Howell, , Milbury et al ., ). In a rabbit model of vesico‐ureteric reflux, consumption of cranberries had a protective effect on E. coli ‐induced oxidative renal damage (Han et al ., ).…”