Ionic high-osmolar contrast medium causes oxidant stress in kidney tissue: partial protective role of ascorbic acid.

It has been known that contrast medium may cause contrast-induced nephropathy in risk groups. This study sought to establish possible effects of ionic high-osmolar contrast medium administration with or without antecedent cisplatin treatment on oxidant/antioxidant status in rat kidney tissues, as well as to investigate a possible protective role of antioxidant ascorbic acid in this regard. Thirty-five female, 14-week-old Wistar-albino rats were used in this study. They were divided into five groups of seven rats (sham, contrast, contrast + ascorbic acid, contrast + cisplatin, and contrast + cisplatin + ascorbic acid). Ascorbic acid was given in a dose of 250 mg/kg/day orally throughout the study period, and cisplatin (10 mg/kg) as a single i.v. dose on the fourth day. Ionic high-osmolar contrast medium (3 gr/kg iodine as a single dose) was administered by i.v. route on the fifth day. After the animals were sacrificed on the sixth day, their kidney tissues were removed surgically to be used in the analyses. Malondialdehyde (MDA) level and activities of antioxidant (superoxide dismutase [SOD], glutathione peroxidase [GSH-Px] and catalase [CAT]) and oxidant (xanthine oxidase [XO]) enzymes were measured in these samples. Serum urea and creatinine levels were measured to evaluate kidney functions. Histopathological investigation of the tissues was also performed. It was observed that contrast medium administration caused increases in MDA levels in the kidney tissues, either alone or together with antecedent cisplatin treatment. However, ascorbic acid prevented the increases in MDA levels in the kidney tissues. Histopathological findings revealed that ionic high-osmolar contrast medium administration alone led to mild acute structural damage, but contrast medium administration together with antecedent cisplatin usage caused severe tubular necrosis. Ascorbic acid supplementation prevented these changes, to a great extent. The results suggest that ionic high-osmolar contrast medium administration, either alone or together with antecedent cisplatin treatment, leads to accelerated oxidative reactions in rat kidney tissues, and ascorbic acid protects in part the kidney tissues against this oxidant stress.