engleski

The involvement of oxidative stress in ochratoxin A and fumonisin B1 toxicity

Ochratoxin A (OTA) and fumonisin B1 (FB1) are nephrotoxic mycotoxins that contaminate various commodities, and humans are constantly exposed to low levels of these mycotoxins. Aim of this study was to find out whether very low doses of OTA and FB1, given separately or combined, induce oxidative stress in rat liver and kidney, and whether their effect is synergistic. The concentration of malondialdehyde (MDA) (1) and protein carbonyls (PCs) (2) and the activity of catalase (3) and superoxide dismutase (SOD) (4) were measured in the liver and kidney of rats orally treated with OTA (5 ng/kg b.w. and 50 ug/kg b.w.) and FB1 (200 ng/kg b.w. and 50 ug/kg b.w.), or their combinations. The lowest doses in this study correspondents to the estimated daily intake for OTA and FB1 for humans in Europe. The concentration of MDA and PCs was higher in the liver and kidney when 50 ug OTA/kg b.w. was applied (P<0.05). In the kidney, this effect was obtained even with a dose as low as 5 ng OTA/kg b.w.. FB1 did not affect MDA and PC concentrations in the liver, while in the kidney 5 ng FB1/kg b.w. was enough to increase MDA concentration (P<0.05). The combination of the lower doses of OTA+FB1 increased the MDA and PC concentration both in the liver and the kidney, compared to controls and animals treated with respective doses of mycotoxins (P<0.05). The combinations of mycotoxins reduced the catalase activity only in the kidney when compared to controls (P<0.05). In contrast to the increased kidney concentrations of MDA and PCs even with very low doses of OTA and FB1, the activity of catalase and SOD does not change. Combinations of OTA+FB1 affected almost all parameters, which indicate their potential to produce oxidative damage.    References: 1. Drury, JA. et al. (1997) Clin Chim Acta 263: 177-185. 2. Mercier, Y. et al. (2004) Meat Sci 66: 467-73. 3. Aebi, H. (1984) Methods Enzymol 105: 121-26. 4. Flohé, L., Ötting, F. (1971) Methods Enzymol 105: 93-104.

ochratoxin A; fumonisin B1

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