engleski

Ochratoxin A induces the increase of malondialdehyde in rat kidney

Mycotoxin ochratoxin A (OTA) is nephrotoxic in all experimental animals. The mechanism of OTA toxicity includes the effect on phenylalanine metabolism and on the mitochondrial function. The other mechanism of OTA toxicity includes the oxidative damage by enhancing free radicals generation followed by increased peroxidation of lipids. The end product of lipid peroxidation is malondialdehyde (MDA), which is commonly measured by use of thiobarbituric acid (TBA) test. The effect of OTA was investigated in adult female Wistar rats treated intraperitoneally with OTA (0.5 mg/kg b.w./day, 3 times a week), and sacrificed 24 h after 1, 3, and 6 treatments, and 21 days after 12 treatments, respectively. The end points of our investigation were the spectrophotometric measurement of MDA concentration and the HPLC determination of OTA concentration in kidney homogenates. The highest increase of the concentration of MDA was found after the first treatment (219ą15 nmol/g tissue, Mean ą SD) and decreased gradually (188ą17, 178ą16 nmol/g tissue) after 3rd and 6th treatment. In the homogenate of kidney of rats given 12 doses, and sacrificed 21 days afterwards, the concentration of MDA did not differ from controls (152ą10 nmol/g tissue). On the contrary the concentration of OTA in rat kidney did not show the same pattern. The concentration of OTA increased gradually up to the sixth treatment. The mean value of OTA concentration and S.E. were 0.7 ą 0.03, 0.9ą0.1 and 2.4ą0.3 mg/g tissue, respectively. In the kidney of rats treated 12 times and sacrificed 21 day afterwards, the concentration of OTA was significantly lower (1.1ą01mg/g tissue). Our results demonstrate that the increase of MDA concentration precedes the accumulation of OTA in the kidney of rats.

ochratoxin A; malondialdehyde; kidney

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