The effect of ochratoxin A on the concentration of protein carbonyls in rats.

The mechanism of ochratoxin A (OTA) toxicity has been found to involve the production of free radicals and consequent oxidative stress. Until now, the only studied pathway of OTA-caused oxidative damage was peroxidation of lipids. The aim of this study was to check whether OTA induced the production of protein carbonyls, markers of protein oxidation. Exposed rats (5 per group) were given daily OTA (0.5 mg kg(-1) b. w., i. p.) for 7 days, 14 days, or 21 days, and control rats solvent only (TRIS). All animals were killed 24 hours after the last treatment. The levels of OTA in plasma, kidney and liver homogenates increased gradually during the whole length of the experiment. The levels of protein carbonyls in kidney homogenates of OTA-treated rats was significantly higher after days 14 and 21 than in controls (P < 0.05). The levels of protein carbonyls in the liver was significantly higher in OTA-treated animals only after day 21 (P < 0.05). These results confirm that oxidative stress is involved in the mechanism of OTA toxicity, and that it causes the oxidation of proteins.