engleski

Ochratoxin A induces oxidative stress in rats

Mycotoxin ochratoxin A (OTA) is produced by Penicillium and Aspergillus spp. that frequently contaminate cereals and other commodities not only in tropical countries but also in countries with mild climate. OTA has hepatotoxic, genotoxic and carcinogenic effect in all tested animal species, and due to its pronounced nephrotoxicity it was supposed to be involved in the development of endemic nephropathy. Mechanism of its toxicity and genotoxicity is not understood. The proposed mechanisms of OTA toxicity involve inhibition of protein synthesis, disturbance of gluconeogenesis, and production of reactive oxygen species. In this study the importance of oxidative stress in the mechanism of OTA toxicity in rats was tested. Adult male Wistar rats were treated orally with multiple daily doses of OTA for 15 days and sacrificed 24 hours after last treatment. The doses of OTA were: 5 ng/kg b.w., 0.05 mg/kg b.w. and 0.5 mg/kg b.w., respectively. The lowest dose used in this study is the estimated daily intake for OTA for humans in Europe. In order to determine the effect of OTA on lipid peroxidation and oxidative damage of proteins, concentrations of malondialdehyde (MDA) and protein carbonyls were measured in liver and kidney homogenate. In liver two higher doses of OTA significantly increased concentration of MDA and protein carbonyls (p<0.05). In kidney, even the lowest OTA dose increased the concentration of MDA and protein carbonyls (p<0, 05). MDA and protein carbonyls concentration increased with the increase of OTA dose. The catalytic activity of antioxidative enzymes catalase and superoxide dismutase (SOD) was measured in liver and kidney homogenate. Only the highest OTA dose significantly decreased catalytic activity of catalase and SOD in liver and kidney (p<0.05). Taking together these results indicate that oxidative stress is involved in OTA toxicity.

ochratoxin A; oxidative stress; malondialdehyde; protein carbonyls; catalse; SOD

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