engleski

Ochratoxin A affects the expression of HSP70 in rat liver

Ochratoxin A (OA), a mycotoxin produced by species of Penicillium and Aspergillus, is a potentimmunosupressive, carcinogenic, teratogenic, and genotoxic agent. Exposure OA causes morphological and functional changes in kidney and liver of experimental animals. We have examined effects of OA on the expression of heat-sssshock protein 70 (Hsp70), a member of highly conserved group of intracellular proteins whose synthesis is increased in response to variety of stress stimuli. Fischer rats were treated by subchronic dose of OA (120ug/kg b.w./day) for 10 days (groupA, n=8), and for 35 days (groupB, n=8). the control group ( groupC) was represented by 8 untreated rats. Hsp 70 has been detected in liver homogenates by SDS-PAGE followed by immunoblotting using specific mAb against Hsp70 family. Our results showed that the amount of Hsp70 present in livers of animals from groupA and C were similar. However, the amount of Hsp70 in livers obtained from animals treated by OA for 35 days (groupB) were decreased. The reduced expression of Hsp 70 caused by Oa could be explained by generalized lower rate of protein synthesis in the presence of OA or by other unknown mechanism, which takes place in the control of expression of Hsp70. This fact opens very interesting questions, e. g. how decreased amount of Hsp70 contributes to the development of morphological and functional changes in liver of animals exposed to OA.

Ochratoxin A; Heat-shock protein 70; rat liver

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