Protective effects of melatonin and indole‐3‐propionic acid against lipid peroxidation, caused by potassium bromate in the rat kidney

Abstract

Potassium bromate (KBrO₃) is classified as a carcinogenic agent. KBrO₃ induces tumors and prooxidative effects in kidneys. Melatonin is a well known antioxidant and free radical scavenger. Indole‐3‐propionic acid (IPA), an indole substance, also reveals antioxidative properties. Recently, some antioxidative effects of propylthiouracil (PTU)—an antithyroid drug—have been found. The aim of the study was to compare protective effects of melatonin, IPA, and PTU against lipid peroxidation in the kidneys and blood serum and, additionally, in the livers and the lungs, collected from rats, pretreated with KBrO₃. Male Wistar rats were administered KBrO₃ (110 mg/kg b.w., i.p., on the 10th day of the experiment) and/or melatonin, or IPA (0.0645 mmol/kg b.w., i.p., twice daily, for 10 days), or PTU (0.025% solution in drinking water, for 10 days). The level of lipid peroxidation products—malondialdehyde + 4‐hydroxyalkenals (MDA + 4‐HDA)—was measured spectrophotometrically in thyroid homogenates. KBrO₃, when injected to rats, significantly increased lipid peroxidation in the kidney homogenates and blood serum, but not in the liver and the lung homogenates. Co‐treatment with either melatonin or with IPA, but not with PTU, decreased KBrO₃‐induced oxidative damage to lipids in the rat kidneys and serum. In conclusion, melatonin and IPA, which prevent KBrO₃‐induced lipid peroxidation in rat kidneys, may be of great value as protective agents under conditions of exposure to KBrO₃. Copyright © 2006 John Wiley & Sons, Ltd.