engleski

Time- and dose- related occurrence of apoptotic cells in kidney epithelium of ochratoxin A treated rats

The reports of ochratoxin A (OTA)-induced apoptotic chantes in tubular epithelium of experimental animals are contradictory. Some authors found severe necrosis without apoptotic changes in the tubular epitehelium of rats exposed to OTA in feed, while the others found karyolmegaly with some necrotic and fewer apoptotic-like cells in rats given OTA intraperitoneally (i.p.). The aim of our investigations was to fund out whether apoptosis could be induced by OTA. Our experiments were performed on female rats treated with single or multiple OTA i.p. doses, and the end-point was the numbef of apoptotic cells seen by light microscopy. Single dose of OTA (1.0 mg/kg b.w.) induced the highest number of kidney tubular epithelical cells to start apoptotic changes 24 hours after treatment (19.3 ; mean). The number of apoptotic cells decreased gradually up to the 6th day after OTA treatment. Multiple dosing with OTA (0, 0.25, 0.50, and 1.0 mg OTA/kg b.w., respectively, 3 times a week for 4 weeks) in rats sacrificed 2 days after the last treatment caused the dose related appearance of apototic cells (0, 40, 70, and 106, respectively). In rats treated with one, three, six, and nine doses of OTA (0.5 mg OTA/kg b.w.) the number of apoptotic cells increased up to the sixth treatment (0.6, 7.8, 112, and 74, respectively). Our results show that the appearance of apoptotic cells caused by OTA in the kidney epithelium of the rats is dose- and time- dependent.

ochratoxin A; epithelial cells; apoptosis; rats

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