engleski

Ochratoxin A and citrinin – partners in crime and cross-border traveling

Ochratoxin A (OTA) and citrinin (CTN) are nephrotoxic mycotoxins commonly found together in grain. EU legislation regulates monitoring of OTA in various commodities ; however, a similar monitoring obligation does not exist for CTN. With the aim of studying the effects of these mycotoxins on mammalian kidneys, adult male Wistar rats were subchronically (21 days) treated with individual and combined oral doses of OTA and CTN. Using spectrophotometry and HPLC methods, the oxidative stress parameters (malondialdehyde – MDA, glutathione – GSH and enzymes – superoxide dismutase, glutathione peroxidase and catalase) and concentrations of these mycotoxins were measured in rat kidneys. The results showed that concentrations of CTN in the kidneys of OTA + CTN treated animals were three up to six times higher in animals given CTN alone. Concentration of OTA were 1-3 μg/g tissue. Rats were also treated with the antioxidant resveratrol (RSV) in order to reduce oxidative stress but its prooxidative effects in some organs was noticed. This encouraged us to study the effects of OTA and CTN on proteins that facilitate their transport across basolateral and brush-border membranes of renal epithelial cells. The immunochemical analyses of rat organic anion and cation transporters (rOats and rOcts) revealed mycotoxin- and transporterrelated changes, as well as differences between the individual and combined effects of the studied mycotoxins on protein expression. Physiologically relevant proteins such as sodium- glucose transporters 1 and 2, actin and Na+/K+- ATPase were generally not affected by the comparable mycotoxin doses. Finally, the combination of the powerful antioxidant resveratrol, OTA and CTN had a strong downregulating effect on almost all of the studied organic anion and cation transporters, exceeding the effects of individual and/or combined OTA and CTN high doses by even affecting the physiologically relevant cytoskeletal protein actin.

mycotoxins, organic anions ; organic cations ; oxidative stress ; transporters

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